Unit plan for gas laws

Assessment in Science Education Dr. Robert D. CraigRobert Craig Fall ‘06

Author: Dr. Robert D. Craig, Ph.D.

Unit Plan- Gas Laws

Rational and Purpose Statement:

This Unit Plan will discuss the Gas Laws. It will include some experiments to involve students on a concrete level. Problems and Laboratory assignment will aid to advance understanding to an Abstract level. Some of the Lesson Plans (experiments) have been adopted from other authors.

The unit will not only discuss Charles’ Law, Boyle’s Law and the Ideal Gas equations, it will also be cross correlated with History, Physics and Earth Science. The Physics of a ball on a string, a book falling to the floor, and a rubber ball in a box, will be used to correlate with molecular motion in the gas phase.

This description of kinetic energy and potential energy could be an excellent way to demonstrate these concepts in a high school physics course.

The Lesson on Graham’s law of effusion in terms of separating uranium for nuclear weapons will be related to WW II development of Atomic Weapons.(History)

The Haber Process will be described in terms of its use in WWI and agriculture. Students will be able to discuss how this process was used during this war.(History)

The lesson on Sources of Pollution will be used to introduce topics of Acid Rain, Global Warming and Atmospheric Pollution.(Earth Science). Students will be expected to conduct group presentations on a selected topic from this lesson. Use of tables, charts, and/or graphs in making arguments and claims in oral and written presentations will be expected regarding their research findings

Interdisciplinary Connections:

Physics: Concept of gravity, Kinetic Energy, Potential Energy, Falling Bodies

History: Joseph Louis Gay-Lussac (French Revolution), Haber Process, Uranium Separation using Grahman’s effusion (WWII), Lord Kelvin (American revolution)

Earth Science: Global Warming, Photochemical Smog, Urban Heat Islands, Acid Rain

Trips: Trips to the Bronx River Alliance, Beats avenue Incinerator (Green Point, Brooklyn), Green Point Sewage Plant would be convenient to qualify lessons.

Day 1 Day 2 Day 3 Day 4 Day 5Aim: How do we describe Kinetic and Potential Energy?

Aim: How do we describe gravity, Energy and Heat?

Aim: How do we describe the motion of Gas Molecules?

Aim: What is Atmospheric Pressure?

Aim: To examine Boyle’s Law.

Day 6 Day 7 Day 8 Day 9 Day 10Aim: To examine Charles’ Law.

Aim: When to use the combined Boyle’s Law Charles’ Law equation.

Aim: What is the Ideal Gas equation?

Aim: To discuss Grahman’s Law of Effusion

Aim: To discuss Dalton’s Law of Partial pressure.

Day 11 Day 12 Day 13 Day 14 Day 15Aim: To describe the The Haber Process

Aim: To discuss Heat of Reaction.

Aim: What is Enthalpy?

Aim: Searching for Proof of a Human Impact on the Climate System

Aim: Student Presentations

Glossary of Chemical Terms

Absolute Zero: The lowest possible temperature, written as 0 K or -273oC

Atmospheric pressure: 1 standard atmosphere (atm) = 760 millimeters of mercury (torr) = 1.01 x 105 pascals

Avogadro’s hypothesis: Equal volumes of gases, measured at the same temperature and pressure, contain equal numbers of particles.

Avogadro’s law: At constant temperature and pressure, the volume of an ideal gas is directly proportional to the number of gas particles present:

V1 = V2

n1 n2

Avogadro’s number: The number of particles in 1 mole; 6.02 x 1023

Boyle’s Law: At constant temperature and mass, the pressure of an ideal gas is inversely proportional to its volume; P1V1 = P2V2

Calorie: A quantity of energy; 1 calorie (1 Cal) is exactly equal to 4.186 joules.

Celsius Scale: The temperature on which the freezing and boiling points of water (at 1 atm) are set at 0 and 100, respectively.

Charles’s Law: A constant pressure and mass, the volume of an ideal gas is directly proportional to the Kelvin temperature: V1 = V2

T1 T2

Combined gas law: At constant mass, the product of the pressure and volume divided by the Kelvin temperature is a constant

P1V1 = P2 V2

T1 T2

Concentration: The “strength” of a solution; the quantity of solute relative to the quantity of solvent.

Density: Mass per unit volume; d = m/V

Diffusion: The movement of one substance through another.

Dynamic equilibrium: The state in which the rates of opposing processes are equal

Effusion: The escape of a gas from a small porous opening; (Graham’s law of effusion)

Endothermic reaction: A reaction that absorbs energy; DH is positive for an endothermic reaction

Enthalpy change (H): The heat energy absorbed or release by a system at constant pressure.

Exothermic reaction: A reaction that absorbs energy; H is positive for an endothermic reaction.

Gas: The phase in which matter has neither definite shape nor definite volume.

Graham’s law of effusion: At constant temperature and pressure, the rate of effusion of a gas is inversely proportional to the square root of its molar mass (or density)

Gram (g): A metric unit of mass.

Haber Process: The commercial procedure by which ammonia is produced from nitrogen and hydrogen

Joule (J): The unit of work and energy in the SI (metric system; 4.184 joules = 1 calorie.

Kelvin (K): A measure of absolute temperature; the Kelvin scale begins at 0 and is related to the Celcius scale by the equation K = C + 273; a temperature difference of 1 K is equal to a temperature difference of 1oC.

Kilo- The metric prefix signifying 1000.

Kilocalorie (kcal): 1000 calories; 4186 joules; 4.186 kilojoules.

Kilojoule (kJ) 1000 joules

Kinetic energy: The energy associated with the motion of an object.

Kinetic molecular theory (KMT): The theory that explains the structure and behavior of idealized models of gases, liquids, and solids.

Liter (L): A unit of volume in the metric system; 1 liter = 1000 cubic centimeters; 1 liter = 1 cubic decimeter; 1 liter is approximately equal to 1 quart.

Molality: The concentration of a solution, measured as the number of moles of solute per kilogram of solvent.

Molar mass: The mass of any atom, element, ion, or compound expressed in grams per mole (g/mol)

Molarity: The concentration of a solution, measured as the number of moles of solute per liter of solution.

Molar volume: The volume occupies by 1 mole of an ideal gas ; 22.4 liters at STP

Mole The number of atoms contained in 12 grams of carbon-12; see also Avogadro’s number.

Mole fraction (X): A measure of concentration that expresses the ration of the umber of moles of a given substance to the total number of moles present Xi = n I / n total

Partial pressure: The individual pressure due to to each gas in a mixture of gases.

Potential energy: The energy associated with the position of an object; a “stored” form of energy

Pressure: The force exerted on an object divided by the surface area of the object; P = F/A

Standard temperature and pressure (STP): 273 K and 1 atmosphere

Temperature: A measure of the average kinetic energy of the particles of a substance

Torr: A unit of pressure equivalent to 1 millimeter of mercury (mm Hg).

Van der Waals forces: All forces involving attractions of polar molecules and nonpolar molecules.

Vapor pressure: The pressure produced by a solid or a liquid when it is in equilibrium with its gas phase.

Day 1:

Activity Set-Up: Demonstration of Potential and Kinetic Energy(authority: Robert Craig) (adapted from Physics CST)

Aim: How do we describe Kinetic and Potential Energy?

I.O./SWABT 1. Define Kinetic and Potential Energy 2. Express the formula for Kinetic and Potential Energy 3. Make calculations using the formula for Kinetic and Potential Energy

CONTENT STANDARD: (THE PHYSICAL SETTING)www.nysed.gov

use kinetic molecular theory to explain rates of reactions and the relationships among temperature, pressure, and volume of a substance

PROCESS STANDARDS:http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.htmlNew York State Learning Standards:The following are addressed in this lesson.

Standard 1: Analysis, Inquiry and DesignMathematical AnalysisStudents will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose questions, seek answers, and develop solutions.

Standard 4: ScienceStudents will understand and apply scientific concepts, principles, and theories pertaining to physical setting and physics.

Standard 6: Interconnectedness: Common Themes

http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.html

http://www.nysed.gov/

Students will understand the relationships and common themes that connect mathematics, and science, and apply the themes to these and other areas of learning.

Materials: Ball on a String

Overhead Transparency

Procedure:

Motivation: Ask students have they ever been on a swing?

Lesson: Imagine someone on a swing. The length of a rope on a playground swing is 2.00 m. What is the maximum speed attainable on the swing if the maximum value of Angle theta is 45o?

We define the potential energy at the lowest point of the path of the swing to be zero. At this point, the swing attains its maximum speed and it s total mechanical energy is kinetic energy only. When the swing is at its maximum height, hmax (O = 45o), the total energy is potential energy only. By the principle of the conservation of energy, mgh max v = 1/2mv2 max , or v max = (2gh max )1/2.

(Students at this point, just have to describe calculation)

Using triangle trigonometry, h max = 2m -2 cos 45o m = 0.586 m . Using g = 9.8 m/s2 and substituting these values into the above expressions results in vmax = 3.89 m/s

For Kinetic Energy: 1/2mv2

M = mass in Kilograms (Kg)V = Velocity in meters/second

For Potential Energy: mgh

M = mass in Kilograms (Kg)h=height in meters (m)g = acceleration due to gravity in meters/second squared (m/s2)

The unit for energy is a Joule, which has units kg m2 /s2

Assessment:

1. What is Kinetic Energy? (in your own words)

2. What is Potential Energy? (in your own words)

3. If Mass = 2 Kg and the acceleration due to gravity, g is 9.8 m/s2, if an object is move to a height of 2 meters, what is the potential energy?

4. If Mass = 5 Kg and velocity, v = 10 meters/sec, what is the Kinetic Energy?

5. Describe a Potential Energy Well (i.e.: Some one on a swing!)

6. Throw a ball vertically up in the air so that it rises about 1 m after leaving your hand. Does it slow down as it rises? Does it speed up as it fall? Can you see this happening, or is it too difficult to judge because things happen so fast?

Day 2:

Activity Set-Up: Demonstration of Potential and Kinetic Energy(Authority: Robert Craig)

Activity Set-Up: Demonstration of Potential and Kinetic Energy and Heat

Aim: How do we describe gravity, Energy and Heat?

I.O./SWABT 1. Apply equations of Kinetic and Potential Energy 2. Discuss the concept of Acceleration due to gravity 3. Make calculations using the formula for Kinetic and Potential Energy 4. Observe heat generated by a falling body (friction).


Use kinetic molecular theory to explain rates of reactions and the relationships among temperature, pressure, and volume of a substance

PROCESS STANDARDS:http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.htmlNew York State Learning Standards:The following are addressed in this lesson.


Standard 6: Interconnectedness: Common ThemesStudents will understand the relationships and common themes that connect mathematics, and science, and apply the themes to these and other areas of learning.

Standard 7: Interdisciplinary Problem SolvingStudents will apply the knowledge and thinking skills of mathematics, and science, to address real-life problems and make informed decisions.



Materials: Text Book Table Top Marbles Ramp


Procedure:

Motivation: Ask students to observe a book dropping to the floor?

Lesson: What Happens when a book is released from the top of a table?

Potential Energy is converted to Kinetic Energy and Heat!

Similarity, when a sled rolls down a hill, potential energy is converted to kinetic, there is also heat generated by friction. When you rub your hands together or any two objects, you generate heat. As the book hits the floor, potential energy is lost to kinetic energy and heat. The unit for heat is called a calorie, and is defined as the heat needed to raise 1 gram of water from 14.5 oC to 15.5 oC.

Can you design an experimental apparatus to measure the conversion of kinetic energy to heat? During the American Revolution, horses were used to bore cannons. Lord Kelvin, noticed that a great deal of heat was generated during this boring process.

A mechanical stir placed in a water bath, can be used to churn water. A subsequent rise in heat will be noticed due to the kinetic energy of the water. He is widely known for developing the Kelvin scale of absolute temperature measurement.

Assessment:

Use dimensional analysis to convert the following (express answers in scientific notation if necessary).

1. 20 Calories = ? joules

2. 78 Joules = ? Calories

3. 4020 Joules = Calories

4 . 448 Kilojoules = calories

5. 3016 Kilocalories = joules

Day 3:

Activity Set-Up: Demonstration of Kinetic Energy(authority: Robert D. Craig)The Lesson was adapted from: www.wikipedia.com/barometer

Aim: How do we describe the motion of Gas Molecules?

I.O./SWABT 1. Descirbe to motion of molecules in the gas phase. 2. Relate heat to kinetic motion of molecules in the gas 3. Use kinetic molecular theory (KMT) to explain the relationships among temperature, pressure, and volume of a substance.


Kinetic molecular theory (KMT) for an ideal gas states that all gas particles: Are in random, constant, straight-line motion Are separated by great distances relative to their size; the volume of the gas particles is considered negligible Have no attractive forces between them Have collision that may result in a transfer of energy between gas particles, but the total energy of the system remains constant. (3b)

PROCESS STANDARDS:http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.html

New York State Learning Standards:The following are addressed in this lesson.


Standard 6: Interconnectedness: Common Themes



http://www.wikipedia.com/barometer

Students will understand the relationships and common themes that connect mathematics, and science, and apply the themes to these and other areas of learning.


Materials: Shoe Box Small rubber Ball


Lesson:

Please imagine a gas molecule in a container. The rubber ball will be used to represent the molecule in the box, a container. The motion of my hands should be related to applying heat to a gas container. As I apply heat (movement) to the Box, the gas molecule (the ball) will move in the x, y and z directions, increasing in Kinetic Energy.

K.E. = 1/2mvx2 + 1/2mvy

2 + 1/2mvz2

The more I move the box, the faster the ball moves. The movement of ball collides with all three side of the box. This is pressure. Pressure is defined as Force/Area in units of Newton/meter squared( metric system). A column of atmosphere is specified to exert 14.7 pounds/square inch at sea level (British system).

We all see the phenomena of gases every day: (1) heat rising from sidewalk to make the air appear wavy; (2) placing air in a flat tire during the winter; (3) the piston cycle in cars to propel them; and of course (4) the weather!

Assessment:

Units of Pressure Conversion:

1. 203 kilopascals = ? Atm

2. 80 mm Hg = ? cm of Hg

3. Consider two gas bulbs of equal volume, one filled with H2 gas at 0oC and 2 atm, the other containing O2 gas at 25 oC and 1 atm. Which bulb has (a) more molecules; (b) more mass ; (c) higher average kinetic energy of molecules; and (d) higher average molecular speed?

4. Express the following in units of pascals and bars:

(a) 455 torr;

(b) 2.45 atm;

(c) 0.46 torr;

(d) 1.33 x 10-3 atm

5. Convert the following to torr:

(a) 1.00 Pa;

(b) 125.6 bar;

(c) 75.0 atm;

(d) 4.55 x 10-10 atm

Day 4

Activity Set-Up: Demonstration of atmospheric pressure (authority: Robert Craig) (adapted from http://www.spartechsoftware.com/reeko/)

Aim: What is Atmospheric Pressure?

I.O./SWABT 1. Equal volume of gases at the same temperature and pressure contain an equal number of particles. (3.4 e)

2. Kinetic molecular theory describes the relationships of pressure, volume, temperature, velocity, and frequency and force of collisions among gas molecules (3.4 c)










Materials: Mounted Classroom Barometer


Homemade Barometer: Measuring Cup Water and Dye Soda Bottle Marker

Procedure:

Motivation: The student will investigate and understand that the phases of matter are explained by kinetic theory and forces of attraction between particles.

Key concepts include: pressure, temperature, and volume;

Lesson:

We all listen to weather reports, sometimes we hear the barometric pressure in 30 inches. What is Barometric Pressure? (wait for student response)

Atmospheric Pressure – Measured with a barometer

This is a Schematic drawing of a simple mercury barometer with vertical mercury column and reservoir at base

A standard mercury barometer has a glass column of about 30 inches (about 76 cm) in height, closed at one end, with an open mercury-filled reservoir at the base. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir.

It consists of a glass container with a sealed body, half filled with water. A narrow spout connects to the body below the water level and rises above the water level, where it is open to the atmosphere. When the air pressure is higher than it was at the time the body was sealed, the water level in the spout will drop below the water level in the body; when the air pressure is lower than it was at the time the body was sealed, the water level in the spout will rise above the water level in the body.

The first barometer of this type was devised in 1643 by Evangelista Torricelli. Torricelli had set out to create an instrument to measure the weight of air, or air pressure, and to study the nature of vacuums. He used mercury, perhaps on a suggestion from Galileo Galilei because it is significantly denser than water.

Boyle's Law is named after the Irish natural philosopher Robert Boyle 1627-1691) who was the first to publish it in 1662.

Demonstation:

Homemade barometer: (adapted from http://www.spartechsoftware.com/reeko)

The air pressure around us greatly affects our weather. Notice how your weatherman always mentions various pressure systems (low pressure system, high pressure system, etc.) and how they will affect tomorrow’s weather. In this experiment, we will create a tool that lets you gauge the pressure of the air around you.

http://en.wikipedia.org/wiki/Image:Hg_barometer.PNG

http://en.wikipedia.org/wiki/Image:Hg_barometer.PNG

1. Fill the measuring cup or glass with water and add some colored dye to it.2. Flip the empty soda bottle upside down into the glass measuring cup.3. Assure that you use a bottle that is just the right size. It should fit snugly in the

measuring cup so that the mouth of the bottle does not touch the bottom of the cup.

4. Assure that the level of the water extends into the neck of the bottle.5. Mark a line on the cup to indicate the water level within the bottle.6. Reexamine the bottle in a few days.

Notice the change in the water level. The amount of air within the bottle is fixed and cannot change since the water extended into the bottle acts as a ‘plug’. Hence, you can consider the amount of air trapped in the bottle as an indicator of the air pressure on the day. You plugged the bottle. When the air pressure increases (as it does in drier weather), the pressure on the surface of the water is greater and the water is forced up into the bottle changing the level of the water.

Assessment:

4.1 Describe what would happen to the barometer in figure 5.1 if the tube holding the mercury has a pinhole at its top.

4.2 Describe how the difference between an inflated and a flat automobile tire show that a gas exerts pressure?

4.3 A sailboat moves across the water making use of the wind. How does the motion of a sailboat demonstrate that gas molecules exert pressure?

4.4 Another instrument use to determine pressure is a manometer. Please digram a manometer and describe how it might be used to determine pressure.

4.5 List some macroscopic and microscopic properties of gases.

Day 5

The Lesson was adapted from: www.wikipedia.com/Boyle_law

Aim: To examine Boyle’s Law

I.O./SWABT : Construct a mathematical expression for the relationship between pressure and volume (i.e. P x V is always equal to a constant value dependent on temperature).



1






http://www.wikipedia.com/Boyle_law



Equipment/Materials:

Basket Ball Erylenmeyer Flask Balloon

Air Pump Deionized Water Hot plate

Overhead projector, transparencies

*There are no major safety concerns associated with this lesson*

Lesson:

Please give your attention to the basketball and air pump. As I pump air into the basketball, it expands. This is Boyle’s law. It is used to describe the motion of a piston in a combustion engine. It can also be used to describe blood flow in the human body. Another example of air expansion is with an increase in temperature. This is Charles’ law which will be discussed next class. If I begin to heat water placed in the flask with the balloon on top, the balloon will obviously expand to due the kinetic energy of molecules, which is an increase in vapor pressure of the water.

The mathematical expression for Boyle's law is:

where:

V is volume of the gas. P is the pressure of the gas. k is a constant, and has units of force times distance. As long as the constant

temperature constraint and the fixed quantity of gas constraint, both explicitly included in the statement of Boyle's law, are not violated, k will be constant.

Boyle's law is commonly used to predict the result of introducing a change, in volume and pressure only, to the initial state of a fixed quantity of gas. The "before" and "after" volumes and pressures of the fixed amount of gas, where the "before" and "after" temperatures are the same (heating or cooling will be required to meet this condition), are related by the equation:

Pafter Vafter = Pbefore Vbefore

In practice, this equation is solved for one of the two "after" quantities to determine the effect that a change in the other "after" quantity will have. For example:

Pafter = Pbefore Vbefore / Vafter

Boyle's law Charles’s Law, and Gay Lussac’s Law form the combied gas law. The three gas laws in combination with Avogadro’s Law can be generalized by the ideal gas law.

Assessment:(Practice Sheet)

1. A sample of helium occupies 521 mL at 1572 mmHg. Assume that the temperature is held constant and determine the volume of the helium at 752 mmHg and the pressure, in mmHg, if the volume is changed to 315 mL.

2. Use kinetic molecular theory to explain Boyle’s law.

3 Under which of the following conditions could you use the equation PiVi = PfVf (a) A gas is compressed at constant T. (b) A gas phase chemical reaction occurs. (c) A container of gas is heated (d) A container of liquid is compressed at constant T.

4. A sample of gas has a volume of 2.0 liters at a pressure of 1.0 atmosphere. When the volume increase to 4.0 liters, at constant temperature, the pressure will be: a. 1.0 Atmb. 2.0 Atmc. 0.50 Atmd. 0.25 Atm

Pafter = Pbefore Vbefore / Vafter

5. What volume will a 300 milliliter sample of a gas at STP occupy when the pressure is doubled at constant temperature?

a. 150 mLb. 450 mLc. 300 mLd. 600 mL

Day 6: Charles’ Law Lab

This lesson was adapted from the version created by http://filebox.vt.edu/users/kmilbour/Portfolio/Ideal%20Gas%20law%20lesson%20plan.htm )

Aim: During this lab, the purpose will be to determine if the temperature affects the size (volume) of a balloon and if so, how it does.

I.O./SWABT

1. Relate the changes in volume of gases to changes in the temperature (i.e. direct relationship).

2. Explain why the volume of a gas increases as the temperature increases. 3. Predict the volume of a gas when its temperature is specified.


use kinetic molecular theory to explain rates of reactions and the relationships among temperature, pressure, and volume of a substance

CONTENT STANDARD G: History and Nature of Science http://books.nap.edu/html/nses/html/6e.html As a result of activities in grades 9-12, all students should develop understanding of

Science as a human endeavor

http://books.nap.edu/html/nses/html/6e.html


http://filebox.vt.edu/users/kmilbour/Portfolio/Ideal%20Gas%20law%20lesson%20plan.htm

http://filebox.vt.edu/users/kmilbour/Portfolio/Ideal%20Gas%20law%20lesson%20plan.htm

Nature of scientific knowledge Historical perspectives





Motivation: Predict how temperature affects the size (volume) of a balloon.

Lesson:

Charles's law is one of the gas laws. It states that at constant pressure, the volume of a given mass of an ideal gas increases or decreases by the same factor as its temperature (in kelvins) increases or decreases.

The law was first published by Joseph Louis Gay-Lussac in 1802, but he referenced unpublished work by Jacques Charles from around 1787. This reference has led to the law being attributed to Charles. The formula for the law is:

-where:

V is the volume. T is the temperature (measured in kelvins). k is a constant.


To maintain the constant, k, during heating of a gas at fixed pressure, the volume must increase. Conversely, cooling the gas decreases the volume. The exact value of the constant need not be known to make use of the law in comparison between two volumes of gas at equal pressure:

.

In simpler form, as the temperature increases the volume of the gas increases

Materials/Equipment:

Round Balloon stringCelsius thermometer

Ruler ice, and bucket hot plate

Marker 400-mL Beaker tongs

Procedure: During this lab, the purpose will be to determine if the temperature affects the size (volume) of a balloon and if so, how it does.

1. Given the equipment, design a lab experiment that will allow you to determine the relationship between volume and temperature. Write out a procedure, step-by-step, so that someone else could accurately repeat your experiment.

2. You are required to find out what happens when the temperature increases as well as when the temperature decreases.

3. Using your data, create a graph that shows the relationship that you concluded exists between volume and temperature.

Results: Create and fill out a data table including all measurements and values that you collected.

** to find radius, use equation: circumference = 2∏r

**to find volume, use equation: volume = 4/3 ∏r3

**SHOW WORK FOR ALL EQUATIONS THAT YOU USE**

Discussion:

1. Briefly describe what your data indicates. (leave 3 lines)

2. How did the circumference of the balloon change as the temperature increased? (leave 3 lines)

3. How is the circumference of the balloon related to temperature? (leave 3 lines)

Conclusions: Accept or reject hypothesis and explain why.

Day 7:

The Lesson was adapted from: http://www.epa.gov/eogapti1/module2/idealgas/idealgas.htmhttp://en.wikipedia.org/wiki/Combined_gas_law

Aim: When to use the combined Boyle’s Law Charles’ Law equation



1





http://en.wikipedia.org/wiki/Combined_gas_law

http://www.epa.gov/eogapti1/module2/idealgas/idealgas.htm

Standard 1: Analysis, Inquiry and DesignMathematical AnalysisStudents will be able to solve problems, using the combined gas law

Standard 4: ScienceStudents will understand and apply scientific concepts, principles, and theories pertaining to the gas laws in terms of KMT (3.4i).



Materials: There are no materials required for this lesson.

Procedure:

Lesson:

Volume (V), temperature (T), moles (n), and pressure (P) are four experimental parameters of gases that are related to each other by gas laws. Laws are generalized observations of experimental evidence, not explanations of why.

Pressure is the force per unit area. With gases the force comes from the gas molecules hitting the side of the container. One unit of pressure is mm Hg, which refers to the height of a column of mercury. Another name for the unit mm Hg is a torr, in honor of the barometer's inventor, Evangelista Torricelli. The average atmospheric pressure at sea level is 760 torr. This leads to another unit of pressure, atmospheres (atm), where 1 atm is exactly equal to 760 torr. Pascals (Pa) are the SI unit of pressure that is based on the definition (force/area) rather than an experimental measurement. 1 Pa = 1 N/m2. A related unit is a bar, where 1 bar = 100 Pa. These two types of units are related by 101,325 Pa = 1 atm.

Changing one of these parameters can affect the others. If temperature and amount of gas are kept constant and pressure is increased, volume will decrease. This is Boyle’s law,

that pressure and volume are inversely proportional. Charles’s Law says that volume is proportional to temperature, when moles of gas and pressure are constant. These two laws can be combined into the combined gas law. Avogadro’s law says that moles are proportional to volume with constant pressure and temperature. The conditions used for comparison of gases are called standard temperature and pressure (STP). Standard temperature is 0°C (273.25 K) and standard pressure is 1 atm (760 torr). The volume of 1 mole of gas at STP is called standard molar volume and has a value of 22.4 L.

For comparing the same substance under two different sets of conditions, the law can be written as:

We can however remove n from the equation because it is constant when changing only the conditions, to make:

(Students at this point, just have to describe calculation)

Assessment:

1. A bicycle pump inflates at tire whose volume is 565 mL under an internal pressure of 6.47 atm at a temperature of 21.7oC. What volume of air at 1.01 atm and 21.7 oC did the pump transfer?

2. A sample of air was compressed to a volume of 20.0L. The temperature was 298 K and the pressure was 5.00 atm. If the sample had been collected from air at P=1.00 atm T=298 K, what was the original volume of the gas?

3. Under which of the following conditions would you not use the equation

P1V1 = P2 V2

T1 T2

(a) P is expressed in torr(b) T is expressed in oC(c) V is changing (d) n is changing

4. A 500 mL sample of a gas at 205 oC and 1.20 atm is cooled to 100 oC and the pressure is increased to 2.9 atm. What is the new gas Volume?

5. A balloon is filled with helium. Its volume is 5.90 L at 26 oC and 1.0 atm. What Is the volume of the balloon at 0.8 atm and 50 oC ?

Day 8:

Activity Set-Up: Students will understand the principles of the Ideal Gas Law and calculate the amount of CO2 gas created in a chemical reaction.

This lesson was adapted from the following web sites: http://www.epa.gov/eogapti1/module2/idealgas/idealgas.htmhttp://www2.wwnorton.com/college/chemistry/gilbert/overview/ch8.htm By Thomas R. Gilbert, Rein V. Kirss, and Geoffrey Davies

http://www.pasco.com/experiments/chemistry/february_2003/home.html#purpose

Aim: What is the Ideal Gas equation?



http://www.pasco.com/experiments/chemistry/february_2003/home.html#purpose

http://www2.wwnorton.com/college/chemistry/gilbert/overview/ch8.htm

http://www.epa.gov/eogapti1/module2/idealgas/idealgas.htm

The concept of an ideal gas is a model to explain the behavior of gases. A real gas is most like an ideal gas when the real gas is at low pressure and high temperature(3.4a)






Materials:

20 oz plastic bottle Bottle of 6.0 M HCl Baking Soda Small test tube Safety goggles

Motivation: Students will understand the principles of the Ideal Gas Law and measure the amount of CO2 gas created in a chemical reaction.

Background Information:

The Ideal Gas Law was written in 1834 by Emil Clapeyron (1799-1864). The Ideal Gas Law is a combined statement of Charles, Gay-Lussac and Boyle's laws and is stated as: PV = nRT,


Where:

P = Absolute PressureV = Absolute VolumeT = Absolute Temperaturen = Number of molesR = Universal gas constant

This law is a generalization and states that for a specified quantity of gas, the product of the volume (V) and pressure (P) is proportional to the absolute temperature (T). The relationship between them may be deduced from kinetic theory.

Since the identity of the gas is irrelevant to the gas laws, the laws work as well for mixtures of gases as a single gas.

Because pressure, volume, temperature, and moles are the only variables, if three of the variables are known, the other can be determined. The relationship between these variables is called the ideal gas law.

PV = nRT

In this equation, R is the gas constant. Its value depends on the units used in the other variables. By rearranging this equation, these experimental parameters can be related to mass, density, and molar mass.

Hypothesis: What is the effect of mixing baking soda and HCl in a soda bottle?

20 oz plastic bottle Bottle of 6.0 M HCl Baking Soda

Small test tube Safety goggles

Procedure:

Pour .65 grams of baking soda (limiting reagent) into the plastic bottle.

Fill the small test tube with HCl (excess reagent). Connect the Balloon the Plastic Container.

Lab Assessment: Conclusions and Extensions:

1. What happened to the pressure during the reaction? Is this evidence of a physical change or a chemical change?

2. What happened to the temperature during the reaction? Is this evidence of a physical change or a chemical change?

3. What is the formula for the chemical reaction that took place?

Answer: NaHCO3 + HCl -> NaCl + CO2 + H2O4. Compare your answer to the expected number of moles (0.00775) of CO2.

Lesson Assessment:

Ideal Gas

The total quantity of molecules contained in 5.6 Liters of as gas at STP is 1. 1.0 mole2. 0.75 mole3. 0.50 mole4. 0.25 mole

If the pressure and Kelvin temperature of 2.00 moles of an Ideal gas at STP are doubled the resulting volume will be

a. 5.60 Lb. 11.2 Lc. 22.4 Ld. 44.8 L

Which quantity represents 0.500 mole at STP?

a. 1.0 moleb. 2. 0 molec. 0.50 moled. 1.5 mole

Under what conditions does a real gas behave most nearly like an ideal gas?

a. High pressure and low temperatureb. High pressure and High temperaturec. Low pressure and low temperatured. Low pressure and High temperature

Day 9:

This Lesson was adapted from the version created by: http://library.thinkquest.org/3310/lographics/experiments/grahams.html And http://www.citycollegiate.com/kmtlight.htm.

Lesson notes were also added from: http://www.ornl.gov/ and http://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory

Aim: To discuss Grahman’s Law of Effusion

I.O./SWABT 1. To measure the relative rates of diffusion of ammonia gas and hydrogen chloride gas.

2. To verify Graham's law of diffusion.



http://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory

http://www.ornl.gov/

http://www.citycollegiate.com/kmtlight.htm

http://library.thinkquest.org/3310/lographics/experiments/grahams.html


CONTENT STANDARD G: History and Nature of Science http://books.nap.edu/html/nses/html/6e.html As a result of activities in grades 9-12, all students should develop understanding of

Science as a human endeavor Nature of scientific knowledge Historical perspectives




Materials:

1. 12M HCl (aq) 2. 15M NH3 3. NaHCO3 4. Glass tube (1 cm * 70 cm) 5. (2) 50-mL beakers 6. (2) Medicine droppers 7. (2) Rubber stoppers 8. (2) Ring stands 9. Meter stick 10. Cotton balls 11. Stopwatch

Procedure:

1. Fit cotton plugs snugly into the ends of the diffusion tube. Close each end loosely with a rubber stopper.


http://books.nap.edu/html/nses/html/6e.html

2. Prepare one small beaker of concentrated HCl and another with NH3. 3. Place a few drops of HCl on one side of the diffusion tube and place a few drops

of NH3 on the other side of the diffusion tube. 4. Immediately replace the stoppers and record the time. 5. A white deposit will form in the tube. As soon as it appears, record the time.

Measure to the nearest 0.1 cm the distance from the inside end of each cotton plug to the center of the white deposit.

Data & Information:

Distance from HCl to product min:sec

Distance from NH3 to product cm

Rate of diffusion of HCl (Distance/Time) cm/sec

Rate of diffusion of NH3 (Distance/Time) cm/sec

Experimental ratio of rates (NH3/HCl) (NH3/HCl)

Theoretical ratio of rates (NH3/HCl) (NH3/HCl)

Lesson:

Graham's law is a quantitative relation between the density and rate of diffusion of gases

“Does anyone know where the inspiration for many “007 – James Bond” Movies comes from? (wait for student response).

There was a great deal of espionage taken place during WWII in order to process the first Nuclear Weapons. There were Secret Agents, Double Secret Agents and so forth.

One ingredient needed to make Nuclear Weapons is heavy Water, D20. The other is a radioactive substance such as Polonium or Uranium.

Uranium can be found in the form of Oxides. Once a large deposit of Uranium Oxide is discovered, Its isotopes U235 and U238 must be separated.

This was the need to separate U238 from U235 during WWII. This was done by Grahman law of effusion. By turning the Oxides of Uranium into a gas, U238 could be separated from U238 !”

This research was done at Oak Ridge National Laboratory in 1943, and was established during WWII when American scientists feared that Nazi Germany was rapidly developing an atomic bomb.(see http://www.ornl.gov/ and http://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory)

Graham's law, also known as Graham's law of effusion, was formulated by Thomas Graham. Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles.

Inter mixing of two or more gases to form a homogeneous mixture without any chemical change is called "DIFFUSION OF GASES" . Diffusion is purely a physical phenomenon. Gases diffuse very quickly due to large empty spaces among molecules. Different gases diffuse with different rates (velocities)

(see . http://library.thinkquest.org/3310/lographics/experiments/grahams.htm)

The rate of diffusion of a gas is inversely proportional to the square root of its density.

The comparative rates of diffusion of two gases are inversely proportional to the square root of their densities

Consider two gases A and B having mass densities d1 and d2 and their rates of diffusions are r1 and r2 respectively. According to Graham's law of diffusion:For gas A:

..................(i)

http://library.thinkquest.org/3310/lographics/experiments/grahams.htm

http://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory

http://www.ornl.gov/

..................(ii)

Dividing equation (i) by equation (ii)

Since density is proportional to molecular mass, therefore, we can replace density d by Molecular mass

Assessement

Calculations:

1. Calculate the rate of diffusion for each gas by dividing the distance traveled (cm) by the time required (sec) for the appearance of the white deposit. Enter the calculated rates above.

2. Calculate the ration between the rate of diffusion of NH3 and the rate of diffusion of HCl, using the rates calculated above. Enter the value for this ratio above.

3. Using the molecular masses of NH3 and HCl, calculate the theoretical ratio between the rates of diffusion of these gases. Enter the value above. (Rate of diffusion = 1/sq. root of molecular mass)

4. Calculate the % error in your experimentally determined value for the ratio of the rates of diffusion of NH3 and HCl. Use the theoretical ratio calculated in question 3 as the accepted value for the ratio. (% error = absolute value of (theoretical ratio - experimental ratio/ theoretical ratio))

Day 10: Dalton ’s Law of Partial Pressure

This Lesson was adapted from the version created byhttp://www.epa.gov/eogapti1/module4/vaporpres/vaporpres.htm

Aim: What is Vapor Pressure?

I.O./SWABT 1. Define partial pressure, vapor pressure, and relative humidity, explain how they are related.








http://www.epa.gov/eogapti1/module4/vaporpres/vaporpres.htm



Materials: There are no materials associated with this lesson.

Lesson:

“What’s your favorite perfume? (wait for student response)

Can anyone name some perfume companies? (Avon, Revlon, etc.) Fragrance company’s are a multimillion dollar industry in the U.S. which employ a great many chemists!

How do perfumes diffuse through a room? (wait for student response) Do you know of some perfumes which are stronger than others?

What ingredient do all or most perfumes have? (wait for student response) they all contain alcohol!

Where might you place perfume on your body? (near your neck or on your wrist, to increase its vapor pressure)

During this lesson, I would like to define:

Vapor pressure and Dalton ’s Law of Partial Pressure

We shall also define: dew point; and humidity;

Dalton ’s Law of Partial Pressure

The pressure of an ideal gas in a mixture is equal to the pressure it would exert if it occupied the same volume alone at the same temperature. This is because ideal gas molecules are so far apart that they don't interfere with each other at all. Actual real-world gases come very close to this ideal.

Clean, dry air contains about 78% nitrogen, 21 % oxygen, and 1% argon (by volume), plus trace amounts of other gases. Oxygen is converted to ozone and then changed back to oxygen in the statosphere.

A consequence of this is that the total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the individual gases in the mixture as stated by Dalton’s Law. For example, given an ideal gas mixture of nitrogren (N2), hydorgen, (H2) and ammonia (NH3) (Haber Process)

where:

= total pressure of the gas mixture

= partial pressure of nitrogen (N2)

= partial pressure of hydrogen (H2)

= partial pressure of ammonia (NH3)

Ideal gas mixtures

The mole fraction of an individual gas component in an ideal gas mixture can be expressed in terms of the component's partial pressure or the moles of the component:

and the partial pressure of an individual gas component in an ideal gas can be obtained using this expression:

where:

xi = mole fraction of any individual gas component in a gas mixture

Pi = partial pressure of any individual gas component in a gas mixture

ni = moles of any individual gas component in a gas mixture

n = total moles of the gas mixture

The mole fraction of a gas component in a gas mixture is equal to the volumetric fraction of that component in a gas mixture.

The total pressure of a system is equal to the sum of the partial pressures.

Ptotal = P1 + P2 + P3 + ………

Example

The total pressure of a system is 64 kPa. The pressure of oxygen is 18 kPa and the pressure of nitrogen is 31 kPa. What is the pressure of the third gas present?

The most common unit for vapor pressure is the torr. 1 torr = 1mm Hg (one millimeter of mercury). The international unit for pressure is: 1Pascal = a force of 1 newton per square meter = 10 dyn/cm² = 0.01 mbar= 0.0075 mmHg

Relative humidity is defined as the ratio of the partial pressure of water vapor in a gaseous mixture of air and water to the saturated vapor pressure of water at a given temperature. Relative humidity is expressed as a percentage and is calculated in the following manner:

where:

is the relative humidity of the gas mixture being considered; is the partial pressure of water vapor in the gas mixture; and

is the saturation vapor pressure of water at the temperature of the gas mixture.

ASSESSMENT:

1. Define partial pressure, vapor pressure, and relative humidity, Explain how there are related.

2. A gas manifold connects three flasks. The first flask contains 1.0 L of He at 180 torr. The second flask contains 1.0 liters of Ne at 0.45 atm. The third flask contains 2.0 L of Ar at 25 kPa. Calculate the partial pressure of each gas and the total pressure when the manifold is opened. (From Zumdahl, Chemistry)

3. The amount of N02 in a smoggy atmosphere was measured to be 0.78 ppm. The barometric pressure was 758.4 torr. Compute the partial pressure of NO2 in the atmosphere.

4. In dry atmospheric air, the four most abundant components are N2, X= 0.7808; O2 , X = 0.2095; Ar, X =9.34 X 10-3 , and CO2, X = 3.25 X 10-4. Calculate the partial pressure of these four gases, in torr, under standard atmospheric conditions.

5. Find the partial pressures, total pressure, and mole fractions of a gas mixture in a 4.00L container at 375 oC if it contains 1.25 g each of Ar, CO, and CH4

6. In 1990, carbon dioxide levels at the South Pole reached 351.5 parts per million by volume (The 1958 reading was 314.5 ppm by volume.) Convert this reading to a partial pressure in atmospheres. At this level, how many CO2 molecules are there in 1.0 L of dry air at -45 oC?

7. A mixture of cyclopropane gas (C3 H6 ) and oxygen ( O2) in 1.00:4.00 mole ration is used as an anesthetic. What mass of each of these gases is present in a 2.00 L bulb at 23.5 oC if the total pressure is 1.00 atm?

8. A gas cylinder of volume 5.00 L contains 1.00 g of Ar and 0.0500 g of Ne. The temperature is 275 K. Find the partial pressures, total pressure,, and mole fractions.

Day 11: The Haber Process:

This lesson was adapted from http://haberchemistry.tripod.com/#History

Activity Set-Up: Students will understand the principles of the Ideal Gas Law and calculate the amount of CO2 gas created in a chemical reaction.

This lesson was adapted from the following web sites: http://www2.wwnorton.com/college/chemistry/gilbert/overview/ch8.htm By Thomas R. Gilbert, Rein V. Kirss, and Geoffrey Davies

CONTENT STANDARDS:

1. Collision theory states that a reaction is most likely to occur if reactant particles collide with the proper energy and orientation (3.4d)

2. Some chemical and physical changes can reach equilibrium (3.4h)3. The rate of a chemical reaction depends on several factors: Temperature,

concentration, nature of reactants, surface area, and the presence of a catalyst (3.4f)4. At equilibrium, the rate of the forward reaction equals the rate of the reverse

reaction. The measurable quantities of reactants and products remain constant at equilibrium. (3.4i)

5. LeChatelier’s principle can be used to predict the effect of stress (change in pressure, volume, concentration and temperature ) on a system at equilibrium (3.4j)6. Describes the concentration of particles and the rates opposing reactions in an equilibrium system (3.4iv).

PROCESS STANDARDS:

http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.htmlStandard 4: Students will: understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science



http://haberchemistry.tripod.com/#History

Standard 6: Interconnectedness: Common Themes History: The Haber Process is a method of producing ammonia developed in WWI.

Standard 6: Interconnectedness: Common Themes Equilibrium and Stability: Equilibrium is a state of stability due either to a lack of changes (static equilibrium) or a balance between opposing forces (dynamic equilibrium).

Materials: Transparencies

There are no other materials needed for this lesson

Lesson:

The Haber Process is a method of producing ammonia developed in WWI. The Germans needed nitrogen to for making their explosives. When the Allies blocked off all trade routes going to and from Germany, they lost all source of sodium nitrate and potassium nitrate, their source of nitrogen. They found their source of nitrogen in the air, which was 80% nitrogen. The chemist Fritz Haber developed the Haber Process in WWI, which takes molecular nitrogen from the air and combines it with molecular hydrogen to form ammonia gas, which the chemical formula is NH 3 .The equation for the reversible reaction is:

N2 (g) + 3H2 (g) 2NH3 (g) + 92 kJ

Below is a diagram of an iron oxide catalyst used in industries to produce ammonia economically.

Le Chatelier’s principle states that if a stress (perturbation) is applied to a system at equilibrium, the equilibrium will adjust to minimize that stress. Consequently, if reactant is added, the reaction must go in a forward reaction to use up that reactant and minimize the stress. Besides changes in concentration, other equilibrium stresses are changes in temperature and pressure.

Uses and Raw Materials

The Haber process is used to manufacture ammonia from nitrogen and hydrogen. Ammonia could then be used to make nitric acid, which reacts with ammonia to create ammonium nitrate, which is a very important fertilizer.

The raw materials for creating ammonia are air for nitrogen (N2(g))and methane and water for hydrogen (H2(g)). Hydrogen is process by taking methane (CH4 (g) ) and reacting it with steam (H20(g)) and thus creating carbon dioxide (CO 2(g)) and hydrogen ( H2(g)) .

The nitrogen (N 2(g)) is obtained from the air by fractional distillation, because the air is made up of 80% nitrogen. Fractional distillation is where they take a substance with another substance mixed together, and since both substances have different boiling points, they heat up the mixture. When the one substance with the lowest boiling point starts to boil it evaporates into a cooling jacket, which then liquidifies and is poured into a beaker or container. Then the next substance starts to boil and does the same thing except the substance is put into a different beaker or container to store it. And this separates all of the components of mixtures and you can get one or more pure substances out of a mixture.

When a reaction is reversible, the reaction can go either forwards or backwards. The forward reaction is the reaction that we want, where the reactants are converted into products. The backward reaction is where the products become the original reactants. The reactions of both occur at the same time. In a closed a system the equilibrium mixture after awhile is reached, where a specific proportion of the mixture exists as reactants and the rest as products. A closed system is where none of the reactants or products can get out into the outside environment. When equilibrium has been reached it doesn't mean that the reactions have stopped. It means that the forward reaction is making products in the same amount as the backward reaction is making reactants. This is called a dynamic equilibrium. Dynamic means moving or changing, to tell you that the reaction is till reacting

Le Chatelier’s Principle

For a reversible reaction, Le Chatelier's Principle states that

"The equilibrium position will respond to oppose a change in the reaction conditions".

Which means that is a product is removed then the equilibrium balance changes to make more of the product. The substance then tries to go back it's original equilibrium. then it repeats the process until nothing of the original substance is left. This is very useful. The reverse is also correct if you remove a reactant, the equilibrium will adjust to make more reactant, this is not useful.

Heat may be treated as reactant (an exothermic reaction) or a product (an endothermic reaction). If heat is removed from an exothermic reaction (cool it down) more product will be produced because the equilibrium will shift to produce it. This will produce heat and also more chemical product that you want in the equilibrium mixture.

If heat is ADDED to an exothermic reaction (raise it temperature) the reverse will happen and less product will be produced in the equilibrium mixture.

For a reversible reaction involving gases:

Increasing the pressure will shift the equilibrium towards the side of the reaction, which has the smaller volume. Decreasing the pressure will shift the equilibrium towards the side of the reaction that has the larger volume.

The industrial conditions for producing ammonia the temperature must be 450ºC to 500ºC. The forward reaction (to form ammonia) is exothermic (it gives out heat). If we remove heat as a product (cooling the reaction down) will result in the equilibrium mixture making richer ammonia.

Since we want ammonia from the Haber Process, why is the reaction conducted at 450ºC? Because all reactions go faster if the temperature is raised.

Reversible reactions, such as the Haber Process, raising the temperature will make the equilibrium mixture richer in nitrogen and hydrogen because forming these from ammonia takes heat in. If we COOL the reaction down the proportion of ammonia will increase but the rate of production will decrease. (because the temperature is LOWER). Ammonia s produced at the atmospheric pressure of 100 atm because it is too expensive to make a high-pressure chemical plant. Running the reaction at 200 atm is the highest pressure with the greatest return value. With a reversible reaction, a catalyst which increases the rate will increase the rate of both the forward and the backward reaction. This is useful because the catalyst will, cause the reaction mixture to reach its equilibrium composition more quickly. The catalyst will not change the equilibrium composition of the substance

Environmental issues

The benefits of using a nitrogenous fertilizers is obvious because the crops grow taller, and are healthier therefore yielding a higher crop and therefore cheaper, more plentiful food. There are always disadvantages. These are after applying the fertilizer and it rains or too much fertilizer is used it gets into the steams or rivers and pollutes them. In the rivers, the fertilizer does the same as it would on land, the river plants grow and algae

grow rapidly because of the abundant food supply. The algae then die in large numbers. The bacteria feeding on the dead plant material use up the oxygen in the water. Fish may then die because of the lack of oxygen in the water. Also too high of nitrates in the drinking water is a health hazard, particularly with infants. Nitrates can interfere with the oxygen flow in the blood stream.

Assessment:

1. The Haber synthesis of ammonia occurs in the gas phase at high temperature (400 to 500oC) and pressure (100 to 300 atm). The starting materials for the Haber synthesis are placed inside a container. Assuming 100% yield, draw a sketch that illustrates the system at the end of the reaction.

2. A 0.1054 g mixture of KClO3 and a catalyst was place in a quartz tube and heated vigorously to drive off all the oxygen as O2 The O2 was collected at 25.17 oC and a pressure of 759.2 torr. The volume of gas collected was 22.96 mL. (a) How many moles of O2 were produced?

(b) How many moles of KClO3 were in the original mixture? (c) What was the mass percent of KClO3 in the original mixture?

3. When heated to 150oC , CuSO4 x 5 H2O loses its water of hydration as gaseous H2O. A 2.50 g sample of the compound is placed in a sealed 4.00 L steel vessel containing dry air at 1.00 atm and 27 oC and the vessel is then heated to 227 oC . What are the final partial pressure of H2O and the final total presure?

Day 12:

Activity Set-Up: To discuss Heat of Reaction.

This lesson was adapted from the following web sites: http://www2.wwnorton.com/college/chemistry/gilbert/overview/ch8.htm By Thomas R. Gilbert, Rein V. Kirss, and Geoffrey Davies

Aim: To discuss Heat of Reaction


1. Chemical and physical changes can be exothermic or endothermic (4.1b)

2. Energy released or absorbed during a chemical reaction (heat of reaction) is equal to the difference between the potential energy of the products and the potential energy of the reactants (4.1d)

3. Heat is the transfer of energy (usually thermal energy) from a body of higher temperature to a body of lower temperature. Thermal energy is associated with the random motion of atoms and molecules.

4. Temperature is a measure of the average kinetic energy of the particles in a sample of matter. Temperature is not a form of energy.

PROCESS STANDARDShttp://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.html New York State Learning Standards:The following are addressed in this lesson.

Standard 1: Analysis, Inquiry and DesignMathematical Analysis




Students will be able to calculate the heat involved in a phase or temperature change for a given sample of matter.



Materials: Transparencies

* There are no materials needed for this exercise*

Lesson:

When HCl is Neutralized with NaOH there is Salt NaCL , and water produced , as well as a significant amount of heat.

During the Forth of July, You might have used a “sparkler” (Strip of Mg) to celebrate the day!

As some flicks a butane lighter, a combustion reaction occurs. The same reaction is used in the piston cycle in automobiles.

In an exothermic reaction, the total energy absorbed in bond breaking is less than the total energy released in bond making. In other words, the energy needed for the reaction to occur is less than the total energy provided. As a result of this, the extra energy is released, usually in the form of heat.

(See http://en.wikipedia.org/wiki/Exothermic_reaction)

Sometimes, Heat can be removed from the surrounding environment

The word endothermic describes a process or reaction that absorbs energy in the form of heat. Its etymology (root meaning) stems from the Greek prefix endo-, meaning “inside”

http://en.wikipedia.org/wiki/Exothermic_reaction

and the Greek suffix –thermic, meaning “to heat”. The opposite of an endothermic process is an exothermic process, one that releases energy in the form of heat.(See http://en.wikipedia.org/wiki/Endothermic)

Some examples of endothermic processes are: Cooking food Melting of ice Depressurising a pressure can

(See http://en.wikipedia.org/wiki/Heat_of_reaction)

The standard enthalpy change or reaction (denoted Ho ) is the enthalpy change that occurs in a system when one mole of matter is transformed by a chemical reaction under standard conditions.

For a generic chemical reaction

nA A + nB B + ... → nP P + nQ Q ...

The standard enthalpy change of reaction Ho rxn , is related with the standard enthalpy change of formation Ho

f of the reactants and products by the following equation:

The standard enthalpy change of formation Hof of the reactants and products.

The standard enthalpy of formation or "standard heat of formation" of a compound is the change of enthalpy that accompanies the formation of 1mole of a substance in its standard state from its constituent elements in their standard states.

A change in the temperature is used to calculate the amount of heat that has been absorbed.

Heat flow is calculated using the relation:

Q = (specific heat) x m x T = Hp (the enthalpy) at constant presure

Where q is heat flow, m is mass in grams, and T is the change in temperature. The specific heat is the amount of heat required to raise the temperature of 1 gram of a substance 1 degree Celcius. The specific heat of (pure) water is 4.18 J/(g.oC)

http://en.wikipedia.org/wiki/Heat_of_reaction

http://en.wikipedia.org/wiki/Endothermic

Assessment:

Define the following (please provide an example):

1. Exothermic

2. Endothermic

3. Combustion

4. The standard enthalpy change of reaction

5. The standard enthalpy of formation

6. The specific heat

Calculate:

7. How much energy is required to heat 250 mL of water from 15 C to 90 C to make a cup of hot chocolate given that the specific heat capacity of water is 4.184 J g-1 K-1

8. Use the same amount of energy that was required to heat the water to heat 250 g of Gold (0.128 J g-1 K-1). What is the final temperature?

9. Heat 50 g piece of copper to 500 C. Then Place in 1 liter of water at 20 C. What is the final Temperature? You can solve this problem algebraically or using successive approximations.

Day 13

This lesson and Laboratroy procedure was adapted from http://chemistry.allinfoabout.com/features/calorimeter.htm

by Dr. Anne Helmenstine

and

Physical properties of matter by Carl Martiken

http://www.iit.edu/~smart/martcar/lesson5/id37.htm

The problem set was developed by S.E. Van Bramer for Chemistry 145 at Widener University and the 1997 regents Exam

Aim: What is Enthalpy?

IO/SWBAT :

1. Understand that Energy is exchanged or transformed in all chemical reactions and physical changes of matter. As a basis for understanding this concept: (a) Students know how to describe temperature and heat flow in terms of the motion of molecules (or atoms) and (b) Students know chemical processes can either release (exothermic) or absorb (endothermic) thermal energy.


4. Chemical and physical changes can be exothermic or endothermic (4.1b)5. Distinguish between endothermic and exothermic reactions, using energy

terms in a reaction equation, H, potential energy diagrams or experimental data (4.1i)

PROCESS STANDARDS:http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.htmlhttp://www.emsc.nysed.gov/ciai/mst/sciencestand/physset45.htm l




http://www.widener.edu/


http://science.widener.edu/~svanbram/chem145/chem145.html

http://science.widener.edu/~svanbram


http://chemistry.allinfoabout.com/features/calorimeter.htm

Standard 1: Analysis, Inquiry and DesignMathematical AnalysisStudents will use mathematical analysis to calculate the heat involved in a phase or temperature change for a given sample of matter (4.2iv)

Standard 4: Sciencedevelop their own mental models to explain common chemical reactions and changes in states

Motivation: How to measure heat flow and enthalpy change using a Coffee Cup Bomb Calorimetry ?

Lesson:

The term enthalpy is composed of the prefix en-, meaning to "put into", plus the Greek word -thalpein, meaning "to heat",

It is often calculated as a differential sum, describing the changes within exo- and endothermic reactions, which minimize at equilibrium Enthalpy change is defined by the following equation:

Where,

ΔH is the enthalpy change Hfinal is the final enthalpy of the system, measured in joules. In a chemical reaction, Hfinal is the enthalpy of the products. Hinitial is the initial enthalpy of the system, measured in joules. In a chemical reaction, Hinitial is the enthalpy of the reactants.

The Bomb Calorimeter

A calorimeter is a device that is used to measure the quantity of heat flow in a chemical reaction. Two common types of calorimeters are the coffee cup calorimeter and the bomb calorimeter the devise has an outer insulated portion which is viewed as the end of the universe—no heat or work can pass it. The contents of the outer insulated container consists of the stell “bomb”, a sample dish within the “bomb”, ignition wires into the “bomb” and touching the chemical sample dish, water surrounding the “bomb”, a stirrer,

http://en.wikipedia.org/wiki/Greek_language

and a thermometer. The contents of the “bomb” are the system and the other contents of insulate container (including the walls of the “bomb”) are the surroundings. The wall of the “bomb” is the boundary. The “bomb” confines the system to constant volume.

From the law of conservation of energy, we can deduce that

The heat transferred from the system = the heat transferred into the surrounding the left term is just the heat of the reaction (qv) and the right term is the sum of the heat absorbed by the water and the heat absorbed by the bomb’s stainless steel walls so we have

-qv = q water + q bomb

Where the negative sign is required because heat is lost from the system (exothermic)

To determine the above we will need the individual values:

Q water = mass of water*(specific heat of water)*(T) and

Q bomb = heat capacity of bomb * T

The heat capacity of the bomb is determined by first doing an experiment with some chemical for which you know the heat of combustion so that you can solve the equations for the heat capacity of the bomb. Then the unknown is run using the previously determined value for the heat capacity of the bomb.

Procedure:

The coffee Cup Calorimeter

Students will begin experiment by Carl Martiken


Back ground Information:

A coffee cup calorimeter is essentially a polystyrene (Styrofoam) cup with a lid. Really, any well-insulated container will work. The cup is partially filled with a known volume of water and a thermometer is inserted through the lid of the cup so that the


thermometer is inserted through the lid of cup so that the thermometer bulb is below the surface. The water absorbs the heat of any chemical reaction taking place in the calorimeter. The change in the water temperature is used to calculate the amount of heat that has been absorbed.

Heat flow is calculated using the relation:

Q = (specific heat) x m x T

Where q is heat flow, m is mass in grams, and T is the change in temperature. The specific heat is the amount of heat required to raise the temperature of 1 gram of a substance 1 degree Celcius. The specific heat of (pure) water is 4.18 J/(g.oC)

For example, consider a chemical reaction which occurs in 200 grams of water with an initial temperature of 25.0 oC. The reaction is allowed to proceed in the coffee cup calorimeter. As a result of the reaction, the temperature of the water changes to 31.0C. the heat flow is calculated:

q water = 4.18 j/(g.oC) x 200 g x (31.0 oC -25.0 oC)

q water = +5.0 x 103 J

In other words, the products of the reaction evolved 5000 J of heat, which was lost to the water. The enthalpy change, H, for the reaction is equal in magnitude by opposite to the heat flow for the water

H reaction = - (q water)

For an exothermic reaction, H < 0; q water is positive. The water absorbs heat from the reaction and an increase in temperature is seen. For an endothermic reaction, H > 0; q water is negative. The water supplies heat for the reaction and a decrease in temperature is seen

A coffee cup calorimeter is great for measuring heat flow in a solution, but it can’t be used for reactions which involve gases, since they would escape from the cup. Also, a coffee cup calorimeter can’t be used for high temperature reactions, since high heat would meld the cup. A bomb calorimeter is used to measure heat flows for gases and high temperature reactions. ‘A bomb calorimeter works the same way as a coffee cup calorimeter, with one big difference. In a coffee cup calorimeter, the reaction takes place in the water. In a bomb calorimeter, the reaction takes place in a sealed metal container, which is placed in the water in an insulated container. Heat flow from the reaction crosses the walls of the

sealed container to the water. The temperature difference of the water is measured, just as it was for a coffee cup calorimeter.

Analysis of the heat flow is a bit more complex than it was for the coffee cup calorimeter because the heat flow into the metal parts of the calorimeter must be taken into account:

q reaction = -(q water + q bomb)

Where q water = 4.18 J/ (g. oC)) x mwater x T

The bomb has a fixed mass and specific heat. The mass of the bomb multiplied by its specific heat is sometimes termed the calorimeter constant, denoted by the symbol C with units of joules per degree Celsius. The calorimeter constant, denoted by the symbol C with units of joules per degree Celsius. The calorimeter constant is determined experimentally and will vary from one calorimeter to the next. The heat flow of the bomb is:

q bomb = C x T

Once the calorimeter constant is known, calculating heat flow is a simple matter. The pressure within a bomb calorimeter often changes during a reaction, so the heat flow may not be equal in magnitude to the enthalpy change.

Energy and Enthalpy Homework Problem Set

This problem set was developed by S.E. Van Bramer for Chemistry 145 at Widener University.

1. What occurs when the temperature of 10.0 grams of water (June ’93) is changed from 15.5 oC to 14.5 oC

a. The water absorbs 10.0 caloriesb. The Water releases 10.0 caloriesc. The water absorbs 155 caloriesd. The water releases 145 calories

2. A piece of titanium metal (mass 452.398 g) is placed in boiling water (100.00 °C). After 20 minutes it is removed from the boiling water and placed in a 1.000 liter container of water at 20.00 °C. The temperature of the water increases to 24.28 °C. What is the specific heat of titanium?

3. Next the same piece of titanium is heated in acetylene flame (like that used for welding) to an unknown temperature. When the pieced of titanium is placed in a 10.000 liter container of water at 20.00 oC the final temperature is now 30.72 oC. What is the temperature of the flame? At what temperature does titanium melt?

4. Calculate the energy required to heat a 155.4 g ice cube that starts in a freezer at -100.0 °C (VERY COLD):

a. Heat from the freezer to ice at 0.0 °C. b. Heat from ice at 0.0 °C to liquid at 0.0°C. c. Heat from liquid at 0.0 °C to liquid at 100.0 °C.



http://science.widener.edu/~svanbram/chem145/chem145.html

http://science.widener.edu/~svanbram

d. Heat from liquid at 100.0 °C to gas at 100.0 °C. e. Heat from gas at 100.0 °C to gas at 200.0 °C. f. Heat from ice at -100.0 °C to gas at 200.0 °C

Day 14

Aim: Proof of a Human Impact on the Climate System

I.O./SWABT: understand and apply scientific concepts, principles, and theories pertaining to the physical setting and recognize the historical development of ideas in science.

Have awareness of:

1. Atmospheric Chemistry

Reactions in the atmosphere between natural elements, man-made chemicals, radiation and the atmosphere's circulation affect us in the near term through processes such as ozone depletion and in the long term through climate change

2. Climate Impacts

Having modeled the climate, the next step is to assess its effect on humans and ecosystems, including the economic impact of rising ocean levels

3.Global Climate Modeling

Three-dimensional general circulationmodels (GCMs) to study Earth's climate, both in the development of numerical modeling methods and in analyzing human-climate interaction


CONTENT STANDARD A: As a result of activities in grades 9-12, all students should develop understanding of the Abilities necessary to do scientific inquiry and Understandings about scientific inquiry

CONTENT STANDARD B:


As a result of their activities in grades 9-12, all students should develop understanding of

Structure and properties of matter Motions and forces Chemical reactions Conservation of energy and increase in disorder Interactions of energy and matter

CONTENT STANDARD D:

As a result of their activities in grades 9-12, all students should develop understanding of

Energy in the Earth system Geochemical cycles Origin and evolution of the Earth system

TEACHING STANDARD E:Teachers of science develop communities of science learners that reflect the intellectual rigor of scientific inquiry and the attitudes and social values conducive to science learning. In doing this, teachers

Display and demand respect for the diverse ideas, skills, and experiences of all students.

Enable students to have a significant voice in decisions about the content and context of their work and require students to take responsibility for the learning of all members of the community.

Nurture collaboration among students. Structure and facilitate ongoing formal and informal discussion based on a shared

understanding of rules of scientific discourse. Model and emphasize the skills, attitudes, and values of scientific inquiry.

PROCESS STANDARDS:http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset13.htmlhttp://www.emsc.nysed.gov/ciai/mst/sciencestand/physset45.htm l

Standard 2

Describe the relationships among air, water, and land on Earthexplain how the atmosphere (air), hydrosphere (water), and lithosphere (land) interact, evolve, and change

Describe volcano and earthquake patterns, the rock cycle, and weather and climate changes

Project 2061 Benchmarks



Science Content Standards (High School)

THE NATURE OF SCIENCE

Aspects of the scientific world view can be illustrated in the upper grades both by the study of historical episodes in science and by reflecting on developments in current science. Case studies provide opportunities to examine such matters as the theoretical and practical limitations of science, the differences in the character of the knowledge the different sciences generate, and the tension between the certainty of accepted science and the breakthroughs that upset this certainty.

Procedure:

1. Students will review two journal articles for discussion next lesson:

2. Students will begin reading in class

Journals for review:

Please use the following journal to formulate your literature response and group presentation: ( this article may be found at: http://www.epa.gov/climatechange/basicinfo.html

Basic Information

Climate Change or Global Warming?

The term climate change is often used interchangeably with the term global warming, but according to the National Academy of Sciences, "the phrase 'climate change' is growing in preferred use to 'global warming' because it helps convey that there are [other] changes in addition to rising temperatures."

Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from:

http://www.epa.gov/climatechange/basicinfo.html

natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun;

natural processes within the climate system (e.g. changes in ocean circulation); human activities that change the atmosphere's composition (e.g. through burning

fossil fuels) and the land surface (e.g. deforestation, reforestation, urbanization, desertification, etc.)

Global warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, "global warming" often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities.

The Earth's climate has changed many times during the planet's history, with events ranging from ice ages to long periods of warmth. Historically, natural factors such as volcanic eruptions, changes in the Earth's orbit, and the amount of energy released from the Sun have affected the Earth's climate. Beginning late in the 18th century, human activities associated with the Industrial Revolution have also changed the composition of the atmosphere and therefore likely are influencing the Earth's climate.

The EPA climate change Web site has four main sections on climate change issues and another section on "What You Can Do" to reduce your contribution.

Science

For over the past 200 years, the burning of fossil fuels, such as coal and oil, and deforestation have caused the concentrations of heat-trapping "greenhouse gases" to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse.

Greenhouse gases are necessary to life as we know it, because they keep the planet's surface warmer than it otherwise would be. But, as the concentrations of these gases continue to increase in the atmosphere, the Earth's temperature is climbing above past levels. According to NOAA and NASA data, the Earth's average surface temperature has increased by about 1.2 to 1.4ºF since 1900. The warmest global average temperatures on record have all occurred within the past 15 years, with the warmest two years being 1998 and 2005. Most of the warming in recent decades is likely the result of human activities. Other aspects of the climate are also changing such as rainfall patterns, snow and ice cover, and sea level.

If greenhouse gases continue to increase, climate models predict that the average temperature at the Earth's surface could increase from 2.5 to 10.4ºF above 1990 levels by

http://www.epa.gov/climatechange/glossary.html#Troposphere

the end of this century. Scientists are certain that human activities are changing the composition of the atmosphere, and that increasing the concentration of greenhouse gases will change the planet's climate. But they are not sure by how much it will change, at what rate it will change, or what the exact effects will be. See the Science and Health and Environmental Effects sections of this site for more detail.

U.S. Climate Policy

The United States government has established a comprehensive policy to address climate change. This policy has three basic components:

Slowing the growth of emissions Strengthening science, technology and institutions Enhancing international cooperation

To implement its climate policy, the Federal government is using voluntary and incentive-based programs to reduce emissions and has established programs to promote climate technology and science. This strategy incorporates know-how from many federal agencies and harnesses the power of the private sector.

In February 2002, the United States announced a comprehensive strategy to reduce the greenhouse gas intensity of the American economy by 18 percent over the 10-year period from 2002 to 2012. Greenhouse gas intensity is a measurement of greenhouse gas emissions per unit of economic activity. Meeting this commitment will prevent the release of more than 100 million metric tons of carbon-equivalent emissions to the atmosphere (annually) by 2012 and more than 500 million metric tons (cumulatively) between 2002 and 2012.

EPA plays a significant role in helping the Federal government reach the United States' intensity goal. EPA has many current and near-term initiatives that encourage voluntary reductions from a variety of stakeholders. Initiatives, such as ENERGY STAR, Climate Leaders, and our Methane Voluntary Programs, encourage emission reductions from large corporations, consumers, industrial and commercial buildings, and many major industrial sectors. For details on these and other initiatives as well as other aspects of U.S. policy, visit the U.S. Climate Policy section of the site.

Greenhouse Gas Emissions

In the U.S., our energy-related activities account for three-quarters of our human-generated greenhouse gas emissions, mostly in the form of carbon dioxide emissions from burning fossil fuels. More than half the energy-related emissions come from large stationary sources such as power plants, while about a third comes from transportation. Industrial processes (such as the production of cement, steel, and aluminum), agriculture,

http://www.epa.gov/climatechange/policy/index.html

http://www.epa.gov/climatechange/effects/index.html


http://www.epa.gov/climatechange/science/index.html

forestry, other land use, and waste management are also important sources of greenhouse gas emissions in the United States.

For a better understanding of where greenhouse gas emissions come from, governments at the federal, state and local levels prepare emissions inventories, which track emissions from various parts of the economy such as transportation, electricity production, industry, agriculture, forestry, and other sectors. EPA publishes the official national inventory of US greenhouse gas emissions, and the latest greenhouse gas inventory shows that in 2004 the U.S. emitted over 7 billon metric tons of greenhouse gases (a million metric tons of CO2 equivalents (MMTCO2e) is roughly equal to the annual GHG emissions of an average U.S. power plant.) Visit the Emissions section of this site to learn more.

Health and Environmental Effects

Climate change affects people, plants, and animals. Scientists are working to better understand future climate change and how the effects will vary by region and over time.

Scientists have observed that some changes are already occurring. Observed effects include sea level rise, shrinking glaciers, changes in the range and distribution of plants and animals, trees blooming earlier, lengthening of growing seasons, ice on rivers and lakes freezing later and breaking up earlier, and thawing of permafrost. Another key issue being studied is how societies and the Earth's environment will adapt to or cope with climate change.

In the United States, scientists believe that most areas will to continue to warm, although some will likely warm more than others. It remains very difficult to predict which parts of the country will become wetter or drier, but scientists generally expect increased precipitation and evaporation, and drier soil in the middle parts of the country. Northern regions such as Alaska are expected to experience the most warming. In fact, Alaska has been experiencing significant changes in climate in recent years that may be at least partly related to human caused global climate change.

Human health can be affected directly and indirectly by climate change in part through extreme periods of heat and cold, storms, and climate-sensitive diseases such as malaria, and smog episodes. For more information on these and other environmental effects, please visit the Health and Environmental Effects section of this site.

What You Can Do

Greenhouse gases are emitted as a result of the energy we use by driving and using electricity and through other activities that support our quality of life like growing food and raising livestock. Greenhouse gas emissions can be minimized through simple measures like changing light bulbs in your home and properly inflating your tires to improve your car's fuel economy. The What You Can Do section of the climate change

http://www.epa.gov/climatechange/wycd/index.html


http://www.epa.gov/climatechange/emissions/index.html

http://www.epa.gov/climatechange/emissions/usinventoryreport.html

http://www.epa.gov/climatechange/emissions/usinventoryreport.html

site identifies 30 action steps that individuals can take to decrease greenhouse gas emissions, increase the nation's energy independence and also save money.

State and local governments and businesses play an important role in meeting the national goal of reducing greenhouse gas intensity by 18 percent by 2012. For example, major corporations, states and local organizations are taking action through participation in a wide range of EPA and other federal voluntary programs.

You can start by assessing your own contribution to the problem, by using EPA's personal greenhouse gas emissions calculator to estimate your household's annual emissions. Once you know about how much you emit, you use the tool to see how simple steps you take at home, at the office, on the road, and at school can reduce your emissions. Visit the What You Can Do section of this site to learn more.

.

To visit the Climate Predictions and SETI Web sites and learn how to participate in these programs, see climateprediction.com and setiathome.ssl.berkeley.edu.

http://scope.educ.washington.edu/outlink/http/setiathome.ssl.berkeley.edu/

http://scope.educ.washington.edu/outlink/http/climateprediction.com/

http://www.epa.gov/climatechange/wycd/index.html

http://www.epa.gov/climatechange/wycd/calculator/ind_calculator.html

http://www.epa.gov/climatechange/wycd/calculator/ind_calculator.html

http://yosemite.epa.gov/gw/statepolicyactions.nsf/webpages/VoluntaryPartnershipPrograms.html

http://www.epa.gov/climatechange/wycd/businesses.html

http://www.epa.gov/climatechange/wycd/stateandlocalgov/index.html

Please use the following journal to formulate your literature response and group presentation:

“Brief Introduction to the Scientific Method and the Scientific Paper”

The scientific method is an approach to investigation based on empirical evidence. Empirical refers to demonstrated evidence as opposed to theoretical speculation or explanations based on faith. The method comprises a consistent and logical manner of framing questions about the world and a systematic way of finding answers to those questions.

The scientific paper is the tool scientists use to publish their results and make them available to the scientific community. The scientific paper traditionally presents information to the reader in a number of sections, each with a specific function to help the reader understand the scientific work. These sections are abstract, introduction, materials and methods, results, discussion, and conclusion. These sections may be well defined and labeled or, as in Science, portions may be embedded in the text.

Abstract

The abstract briefly summarizes the research article. It presents the scientific question the research project tries to answer and puts the research result in a larger context. It may also briefly describe each step of the research.

Introduction

The introduction presents the scientific question the research tried to answer and also provides the reader with relevant background information, usually through discussion of related referenced items. In some papers, progress up to the current set of experiments is presented in chronological order, whereas other papers present a conceptualization of the problem as a whole. The introduction often summarizes the methods and conclusions and explains the scientific importance of the research.

Materials and Methods

The materials and methods used in the investigation may be explained in the paper or the original source may be cited as a reference. Science prefers to rely on references to

describe methods as much as possible and include additional details only as they diverge from previous descriptions of methods. The materials and methods section provides readers with the information necessary to replicate the research. Any scientific result must be available for validation and it is necessary to know the methods in order to do the validation. Validation confirms the results. This section also tells readers how the research was done and what criteria and methodology were applied, allowing readers to do their own critical thinking.

Results

This is the section where all valid data from the research are presented. This part of the scientific paper has gone through major changes lately. In this new era of large databases, it has become virtually impossible to present all the data in a manuscript published in print. Today, large groups of data are often presented on the Web as supplemental material or organized databases so the reader can access the data and even search and sort the data. For example, some of the data that originated from the research described in the scientific paper on genomics is available as supplemental material published only on the Web.

Discussion

In this section, the authors interpret their results. They may draw new hypotheses to explain their findings or they may confirm the validity of their original hypothesis. The implications of the results in the context of larger scientific debates and problems are often presented in this section of the paper.

Conclusions

This is the area where the authors summarize their findings and hypotheses and where they make suggestions for future investigations. In this section, the reader may gain an additional understanding of the assumptions the authors have made throughout the paper.

Day 15

Aim: Searching for Proof of a Human Impact on the Climate System

Activity: Students will construct a list of detrimental activities carried out on the environment whether Human developed or be Natural causes.


CONTENT STANDARD A: As a result of activities in grades 9-12, all students should develop understanding of the Abilities necessary to do scientific inquiry and the

Understandings about scientific inquiry

CONTENT STANDARD B: As a result of their activities in grades 9-12, all students should develop understanding of

Structure and properties of matter Motions and forces Chemical reactions Conservation of energy and increase in disorder Interactions of energy and matter 1

CONTENT STANDARD D: As a result of their activities in grades 9-12, all students should develop understanding of the Energy in the Earth system,Geochemical cycles and the Origin and evolution of the Earth system

Participate in group discussions on scientific topics by restating or summarizing accurately what others have said, asking for clarification or elaboration, and expressing alternative positions.




http://www.emsc.nysed.gov/ciai/mst/sciencestand/physset45.htm l

Standard 2

Describe the relationships among air, water, and land on Earthexplain how the atmosphere (air), hydrosphere (water), and lithosphere (land) interact, evolve, and change

Describe volcano and earthquake patterns, the rock cycle, and weather and climate changes

Project 2061 Benchmarks

Science Content Standards (High School)

THE NATURE OF SCIENCE

Aspects of the scientific world view can be illustrated in the upper grades both by the study of historical episodes in science and by reflecting on developments in current science. Case studies provide opportunities to examine such matters as the theoretical and practical limitations of science, the differences in the character of the knowledge the different sciences generate, and the tension between the certainty of accepted science and the breakthroughs that upset this certainty.

Procedure :

1. Students will choose from a list to pick a topic to research as a group

2. Students will present topic in groups of 4-5 students each as a poster or power point assignment

3. Students will also present material in a verbal fashion in the form of a speech with the written or computerized assignment

Topics Include:

Places: Chernobyl, Hiroshima, Rain Forest

People: Al Gore, Sting

Natural Events: describe volcano and earthquake patterns, the rock cycle, and weather and climate changes


Urban (Human) contribution to pollution: What is a Urban Heat Island?

What is NASA? How do they monitor the Earth Ecosystem?

Awareness: What is Earth Day?

Lesson:

Here are some research questions for student projects:

Photochemical Smog

1. What are the chemical components of photochemical smog?

2. What weather conditions characterize photochemcial smog?

3. Under what conditions do nitrogen and oxygen combine? Give the equation.

4. Give the equation for the reaction of nitric oxide with oxygen to form nitrogen dioxide

5. What is the main source of hydrocarbons in polluted air?

6. What are catalytic converters? How do they work?

The Ozone Layer

1. How do free radicals destroy the ozone layer?

2. What are CFC’s?

3. What health effects might result from depletion of the ozone layer?

Acid Rain

1. What is acid rain? How is it formed?2. How might acid rain be alleviated?3. What is the effect of acid rain on iron? Give an explanation.4. What is the effect of acid rain on marble? Give the equation.

Global Warming

1. What is the green house effect?2. How can global warming be alleviated?

Students will begin to prepare written and group presentations based upon their respective topics.

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