Chapter 3: Matter and Energy Classification of Matter Properties of Matter Temperature Energy...

Chapter 3: Matter and Energy

Classification of Matter

Properties of Matter

Temperature

Energy

Specific Heat

Chapter 3 - Slide 2 of 65

Matter

Matter

• Is the material that makes up all things.

• Has mass and occupies space.

Copyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


Matter• Anything that has mass and takes up space.

Matter

Pure Substance Mixture



• Pure Substances: A form of matter that always has a definite and constant composition.

Properties always the same under a given set of conditions (temperature & pressure)


A pure substance is classified as

• An element when composed of one type of atom.

• A compound when composed of two or more different elements combined in a definite ratio.

Pure Substances


Pure Substances: Elements

• Element – Pure substance that can not be broken down into simpler

substances by chemical means.

Copper (Cu)Lead (Pb)Aluminum (Al)

– The most basic form of matter.– Each element can be found on the periodic table.


Pure Substances: Compounds

• Compounds – A chemical combination of 2 or more different

elements.– A pure substance that can be broken down into

simpler substances by chemical means.

Salt (NaCl)Table sugar (C12H22O11)Water (H2O)Carbon monoxide (CO)NOTE: CO is different from the element Co


Elements in a Compound

“Table salt” is a compound that contains the elements sodium and chlorine.

Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings


Pure SubstancesElements and Compounds

• Elements and compounds have definite compositions, and each has a set of properties that are unique.

• Which pairs of symbols / formulas represent elements and compounds respectively?

(A)

(B)

(C)

(D)

(E)

P-1


Mixtures

A mixture is a type of matter that consists of• Two or more substances that are physically

mixed, not chemically combined.• A physical combination of two or more pure

substances in which each substance retains its own chemical identity.

• Two or more substances in different (variable) proportions.

• Substances that can be separated by physical methods.


MixturesExample of a mixture:

• Pasta and water can be separated by using a strainer.

• Uses a physical method to separate the components.



Homogeneous Mixtures

In a homogeneous mixture,

• The composition is uniform throughout.

• The different components of the mixture are not visible or discernable, one from the other. Copyright © 2008 by Pearson Education, Inc.

Publishing as Benjamin Cummings


Heterogeneous Mixtures

In a heterogeneous mixture,

• The composition of substances is not uniform.

• The composition varies from one part of the mixture to another.

• The different parts of the mixture are visible.






Elements v. Compounds v. Mixtures

• Identify the following as an

Q-1

to

Q-5


Matter

Matter

• Has characteristics called physical and chemical properties.


Physical Properties

Physical properties are:

• Characteristics observed or measured without changing the identity of a substance.

• Shape, physical state, odor, boiling and freezing points (Changes of state), density, and color of that substance.


Physical Properties of Copper

Copper has the followingphysical properties:• Reddish-orange

• Very shiny

• Excellent conductor of heat and electricity

• Solid at 25C• Melting point 1083C• Boiling point 2567 C Copyright © 2008 by Pearson Education, Inc.

Publishing as Benjamin Cummings


A physical change occurs in a substance if there is

• A change in the state.

• A change in the physical shape.

• No change in the identity and composition of the substance.

Physical Change


States of Matter

The states of matter are

• Solid

Definite volume and shape

• Liquid

Definite volume, but take the

shape of its container

• Gas

No definite volume or shape Copyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


Examples of States of Matter

Solids• Rocks, shells, baseballs, tennis racquets,

books

Liquids• Lakes, rain, melted gold, mercury in a

thermometer

Gases • Air, helium in a balloon, neon in a neon

tube


Examples of Changes of State

Some changes of state for water:

• Solid water (ice) melts and forms liquid water.

• Liquid water boils and forms gaseous water (steam).



Examples of Physical Changes

Examples of physical changes:

• Paper torn into little pieces (change of size)

• Copper hammered into thin sheets (change of shape)

• Water poured into a glass

(change of shape)



Chemical Properties

Chemical properties describe the ability of a substance

• To interact with other substances• To change into a new substance

Example:

Iron has the ability to form rust

when exposed to oxygen.Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings


Chemical Change

In a chemical change, a new

substance forms that has

• A new composition

• New chemical properties

• New physical properties



Some Chemical Changes

Silver tarnishes Shiny metal reacts to form black, grainy coating.

Wood burns A piece of wood burns with a bright flame to form ash, carbon dioxide, water vapor, and heat.

Iron rusts A shiny nail combines with oxygen to form orange-red rust.


Classify each of the following changes as physical or chemical

A. Burning a candle.

B. Ice melting on the street.

C. Toasting a marshmallow.

D. Cutting a pizza.

E. Iron rusting in an old car.

Learning Check


Temperature

Temperature

• Is a measure of how hot or cold an object is compared to another object.

• Indicates that heat flows from the object with a higher temperature to the object with a lower temperature.

• Is measured using a thermometer.



Temperature Scales

Temperature scales

• Are Fahrenheit, Celsius, and Kelvin.

• Have reference points for the boiling and freezing points of water.



Learning Check P-2


• On the Fahrenheit scale, there are 180°F between the freezing and boiling points and on the Celsius scale, there are 100°C.

180°F = 9°F = 1.8°F 100°C 5°C 1°C

• In the formula for calculating the Fahrenheit temperature, adding 32 adjusts the zero point of water from 0°C to 32°F.

TF = 9/5 TC + 32

or TF = 1.8 TC + 32

Fahrenheit Formula


Solving for °F TemperatureA person with hypothermia hasa body temperature of 34.8°C.What is that temperature in °F?

TF = 1.8 TC + 32

TF = 1.8 (34.8°C) + 32°

exact tenth's exact

= 62.6 + 32°

= 94.6°F

tenth’sCopyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


• TC is obtained by rearranging the equation for TF.

TF = 1.8TC + 32

• Subtract 32 from both sides.

TF - 32 = 1.8TC ( +32 - 32)

TF - 32 = 1.8TC

• Divide by 1.8 = °F - 32 = 1.8 TC

1.8 1.8

TF - 32 = TC

1.8

Celsius Formula


The normal temperature of a chickadee is 105.8°F.

What is that temperature on the Celsius scale?

1) 73.8 °C

2) 58.8 °C

3) 41.0 °C

Learning Check


A pepperoni pizza is baked at 455°F. What

temperature is needed on the Celsius scale?

1) 423°C

2) 235°C

3) 221°C

Learning Check


On a cold winter day, the temperature is –15°C.

What is that temperature in °F?

1) 19 °F

2) 59°F

3) 5°F

Learning Check


The kelvin temperatureHas 100 units between freezing and boiling

points. 100 K = 100°C or 1 K = 1 °C

• Adds 273 to the Celsius temperature.

TK = TC + 273

• 0 K (absolute zero) is the lowest possible temperature .

0 K = –273 °C

Kelvin Temperature Scale


Temperatures

Table 3.6



Learning Check P-8


Energy

• Makes objects move.

• Makes things stop.

• Is needed to “do work”.

Energy


Work

Work is done when • You climb.• You lift a bag of

groceries.• You ride a bicycle.• You breathe.• Your heart pumps

blood.• Water goes over a

dam.Copyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


Potential EnergyPotential energy isenergy stored for use ata later time. Examples are• Water behind a dam.• A compressed spring.• Chemical bonds in

gasoline, coal, or food. Copyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


Kinetic EnergyKinetic energy is the energy of matter in motion.

Examples are

• Swimming.

• Water flowing over a dam.

• Working out.

• Burning gasoline.



Learning Check

Identify the energy as potential or kinetic.

1. Roller blading.

2. A peanut butter and jelly sandwich.

3. Mowing the lawn.

4. Gasoline in the gas tank.


Forms of EnergyEnergy can take many forms.

• Heat (thermal)

• Mechanical (movement)

• Light

• Electrical

• Chemical

• Nuclear

P-3


Changes in Forms of Energy

Energy can change from one form to

another.



Heat is measured in joules or calories.

• 4.184 Joules (J) = 1 calorie (cal)

Exact by definition

• 1 kJ = 1000 J

• 1 kilocalorie (kcal) = 1000 calories (cal)

Units for Measuring Energy or Heat


Examples of Energy In Joules



Learning CheckHow many calories are obtained from a pat of butter if it

provides 150 J of energy when metabolized?

Solution →


SolutionHow many calories are obtained from a pat of butter if

it provides 150 J of energy when metabolized?

Given: 150 J Need: caloriesPlan: J cal

Equality: 1 cal = 4.184 J

Set Up: 150 J x 1 cal = 36 cal 4.184 J


Specific heat

• Is different for different substances.

• Is the amount of heat (q) that raises the temperature of 1 g of a substance by 1°C.

• In the SI system has units of J/gC.

• In the metric system has units of cal/gC.

Specific Heat


Examples of Specific Heats

Table 3.7


Note: Small values indicate good conductor of heat.


SolutionWhat is the specific heat of a metal if 24.8 g absorbs275 J of energy and the temperature rises from 20.2C to 24.5C?

Given: 24.8 g, 275 J, 20.2C to 24.5C Need: J/gC

Plan: SH = Heat/gΔC where ΔoC = (Tf – Ti)

ΔT = 24.5C – 20.2C = 4.3 C SH Equation: SH = heat (q) (mass)(T)

Set Up: 275 J = 2.6 J/gC

(24.8 g)(4.3C)


Rearranging the specific heat expression givesthe heat equation.

Heat(q) = g x Δ°C x J = J g°C

The amount of heat lost or gained by a substanceis calculated from the

• Mass of substance (g).

• Temperature change (T or Δ°C ).

• Specific heat of the substance (J/g°C).

Heat Equation


A layer of copper on a pan has a mass of 135 g. How much heat in joules will raise the temperature of the copper from 26°C to 328°C if the specific heat of copper is 0.385 J/g°C?

The temperature change is 328°C - 26°C = 302°C.

heat (J) = g x T x SH(Cu)

135 g x 302°C x 0.385 J g °C

= 15 700 J or 1.57 x 104 J

Using Specific Heat


How many kilojoules are needed to raise the temperature of 325 g of water from 15.5°C to 77.5°C?

77.5°C – 15.5°C = 62.0°C

heat = g x T x SH

325 g x 62.0°C x 4.184 J x 1 kJ

g °C 1000 J

= 84.3 kJ

Solution


Calculating MassAluminum is used to make kitchen utensils. What is the mass of an aluminum spatula if 3.25 kJ of heat raise its temperature from 20.0°C to 45.0°C. SHAl = 0. 897 J/g°C?

Given: 3.25 kJ (3250 J), 20.0°C to 45.0°C

ΔT = 25.0°C

Plan: Solve heat equation for mass in grams

g = heat

ΔT x SH

Set Up: 3250 J

25.0°C x 0.897 J/g oC

= 145 g Al


Transferring Heat Energy

Heat energy

• Flows from a warmer object to a colder object.

• Provides kinetic energy for the colder object.

• Energy lost by the warmer object is equal to the heat energy gained by the colder object.


Calorimeters and Heat Transfer

A calorimeter

• Is used to measure heat transfer.

• Can be made with a coffee cup, water, and a thermometer.

• Indicates the heat lost by a sample and gained by water.

Heat lost (-q) = Heat (q) gainedCopyright © 2008 by Pearson Education, Inc.Publishing as Benjamin Cummings


Measuring Heat ChangesA 50.0-g sample of tin is heated to 99.8°C and dropped into 50.0 g water at 15.6°C. If the final temperature is 19.8°C, what is the specific heat of tin?

Heat gain (q) by water

= 50.0 g x 4.2°C x 4.184 J/g °C = 880 J

Heat loss (-q) by tin = -880 J

SH tin = -880 J = 0.22 J/g°C

(50.0 g)(-80.0°C)


Energy and Nutrition

On food labels, energy is shown as the nutritional Calorie, written with a capital C. In countries other than the U.S., energy is shown in kilojoules (kJ).

1 Cal = 1000 cal1 Cal = 1 kcal1 Cal = 4184 J

1 Cal = 4.184 kJ


Caloric Food Values

The caloric or energy

values for 1 g of a food

is given in

• kJ or

• kcal (Cal)

Table 3.8



Energy Values for Some Foods


Table 3.9


Energy Requirements

The amount of energy needed eachday depends on• Age• Gender• Physical activity

Table 3.11



A cup of whole milk contains 12 g carbohydrate, 9.0 g fat, and 9.0 g protein. How many kcal (Cal) does a cup of milk contain?

1) 50 kcal (50 Cal)

2) 80 kcal (80 Cal)

3) 170 kcal (170 Cal)

Learning Check

Solution →

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Chapter 3: Matter and Energy Classification of Matter Properties of Matter Temperature Energy...

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