What is Chemistry ?

• Def’d 1 –

the branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances

• Def’d 2 – the complex emotional or psychological interaction between two people

STATES OF MATTER”SUCCESS IS NOT THE KEY TO HAPPINESS. HAPPINESS IS THE KEY TO SUCCESS. IF YOU LOVE WHAT YOU ARE DOING, YOU WILL BE SUCCESSFUL”.

ALBERT SCHWEITZER

Ch.1 J.C. Rowe

Windsor University School of Medicine

Chapter 1 – States of Matter

The Four States of Matter

Basis of Classification of the Four Types

Based upon particle arrangementBased upon energy of particlesBased upon distance between particles

STATES OF MATTER

SOLID LIQUID GAS PLASMA

Tightly packed, in a regular pattern

Vibrate, but do not move from place to

place

Close together with no regular

arrangement.Vibrate, move

about, and slide past each other

Well separated with no regular

arrangement.Vibrate and move

freely at high speeds

Has no definite volume or shape

and is composed of electrical charged

particles

All matter, regardless of state, undergoes physical and chemical changes.

These changes can be microscopic or macroscopic.

A physical change occurs when the substance changes state but does not change its chemical composition. For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc.

The form of appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)

• Melting point

• Boiling point

• Vapor pressure

• Color

• State of matter

• Density

• Electrical conductivity

• Solubility

• Adsorption to a surface

• Hardness

A chemical change occurs when a substance changes into something new.

This occurs due to heating, chemical reaction, etc.

One can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes.

Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).

• Reaction with acids

• Reaction with bases (alkalis)

• Reaction with oxygen (combustion)

• Ability to act as oxidizing agent

• Ability to act as reducing agent

• Reaction with other elements

• Decomposition into simpler substances

• Corrosion

Physical and chemical properties may be intensive or extensive.

Intensive properties such as density, color, and boiling point

These properties do not depend on the size of the sample of matter and can be used to identify substances.

Extensive properties such as mass and volume do depend on the quantity of the sample.

Physical properties are those that we can determine without changing the identity of the substance we are studying.

The physical properties of sodium metal can be observed or measured.

It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.

Hardness, color, melting point and density are all physical properties.

Chemical properties describe the way a substance can change or react to form other substances.

These properties, then, must be determined using a process that changes the identity of the substance of interest.

One of the chemical properties of alkali metals such as sodium and potassium is that they react with water.

To determine this, we would have to combine an alkali metal with water and observe what happens.

In other words, we have to define chemical properties of a substance by the chemical changes it undergoes.

There is no observable change in the quantity of matter during a chemical reaction or a physical change.

In other words, matter cannot be created nor destroyed. It is just converted from one form to another

SolidsLiquidsGasesPlasma

(And how the Kinetic Molecular Theory affects each)

Have a definite shapeHave a definite volumeSolids have an infinite number of free surfaces.

Molecules are held close together and there is very little movement between them.

Kinetic Molecular Theory

Have an indefinite shapeHave a definite volumeLiquids have one free surface.

Kinetic Molecular Theory:Atoms and molecules have more space between them than a solidBut less than a gas (ie. It is more “fluid”.)

Have an indefinite shapeHave an indefinite volume

Kinetic Molecular Theory:

Molecules are moving in random patterns with varying amounts of distance between the particles.

At 100°C, water becomes water vapor, a gas. Molecules can move randomly over large distances.

Below 0°C, water solidifies to become ice. In the solid state, water molecules are held together in a rigid structure.

Between 0°C and 100 °C, water is a liquid. In the liquid state, water molecules are close together, but can move about freely.

Changing states requires energy in either the form of heat.

Changing states may also be due to the change in pressure in a system.

Heat of formation, Hf. Heat of vaporization, Hv

CHANGES OF STATE

SOLID

LIQUID

GASsublimation

Melting

MeltingFreezing

Boilin

g

Boilin

g

Conden

satio

n

Conden

satio

n

Plasma is by far the most common form of matter.

Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible.

On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. We have learned to work, play, and rest using these familiar states of matter.

On August 31, 2012 a long prominence/filament of solar material that had been hovering in the Sun's atmosphere,

the corona, erupted out into space at 4:36 p.m.

Plasma Cont.

Sir William Crookes, an English physicist, identified a fourth state of matter, now called plasma, in 1879.

Plasma temperatures and densities range from relatively cool and tenuous (like aurora) to very hot and dense (like the central core of a star). Ordinary solids, liquids, and gases are both electrically neutral and too cool or dense to be in a plasma state.

The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir, an American chemist and physicist, in 1929.

Plasma Cont.Plasma consists of a collection of free-moving electrons

and ions - atoms that have lost electrons. Energy is needed to strip electrons from atoms to make plasma. The energy can be of various origins: thermal, electrical, or light (ultraviolet light or intense visible light from a laser). With insufficient sustaining power, plasmas recombine into neutral gas.

Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.

Products manufactured using plasmas impact our daily lives:

EXAMPLES:Computer chips and integrated circuits

Computer hard drives

Electronics

Machine tools

Medical implants and prosthetics

Audio and video tapes

Aircraft and automobile engine parts

Printing on plastic food containers

Energy-efficient window coatings

High-efficiency window coatings

Safe drinking water

Voice and data communications components

Anti-scratch and anti-glare coatings on eyeglasses and other optics

For water sterilization, intense UV emission disables the DNA of microorganisms in the water which then cannot replicate. There is no effect on taste or smell of the water and the technique only takes about 12 seconds.

This plasma-based UV method is effective against all water-born bacteria and viruses. Intense UV water purification systems are especially relevant to the needs of developing countries because they can be made simple to use and have low maintenance, high throughput and low cost.

Plasma-based UV water treatment systems use about 20,000 times less energy than boiling water!

                  

Kinetic Molecular Theory

PHASE CHANGES OR CHANGES OF STATE

Triple Point—combination of temperature and pressure where all three phases coexist

Kinetic Molecular Theory PHASE CHANGES OR CHANGES OF STATE

Phase Change Heat Curve for Water

-25

0

25

50

75

100

125

0 20 40 60 80 100 120Joules/Energy --->

Tem

pera

ture

, C

a

b c

d e

f

a to b: solid increases in temperature.

b to c: solid melts to liquid at a constant temperature

c to d: liquid increases in temperature

d to e: liquid vaporizes to gas at a constant temperature

e to f: gas increases in temperature

Latent Heat

•Describes - the amount of energy that is released or absorbed by a body or any thermodynamic system during a time period of constant- temperature.

• During this period a change of state is often observed

Molar Heats of Fusion and VaporizationPhase Change Heat Curve for Water

-25

0

25

50

75

100

125

0 20 40 60 80 100 120Joules/Energy --->

Tem

pera

ture

, C

a

b c

d e

f

Molar heat of fusion: the energy required to melt one mole of a substance. (ΔHfusion)

Molar heat of vaporization: the energy required to vaporize one mole of a substance. (ΔHvaporization)

ΔHfu

sion

ΔHvaporization

Molar Heat of Fusion: Defined

-The amount of heat necessary to melt (or freeze) 1.00

mole of a substance at its melting point

- Note the three important points:

1) It's 1.00 mole of a substance

2) there is no temperature change

3) there is a change of state

Molar Heats of Fusion and VaporizationPhase Change Heat Curve for Water

-25

0

25

50

75

100

125

0 20 40 60 80 100 120Joules/Energy --->

Tem

pera

ture

, C

a

b c

d e

f

Molar heat of fusion: the energy required to melt one mole of a substance. (ΔHfusion)

Molar heat of vaporization: the energy required to vaporize one mole of a substance. (ΔHvaporization)

ΔHfu

sion

ΔHvaporization

Molar Heat of Vaporization: Defined

-The energy required in calories to completely convert

one mole (18g) of water to steam without increasing the

temperature is called the latent heat of vaporization. It

is called latent heat because the water does not go

through a change in temperature as it changes state

Please note 2 things:

1) 1 mole of water

2) Liquid to steam (gas / vapour)

Molar Heats of Fusion and VaporizationCalculations

Example 1:How much energy is required to melt 10.0 grams of ice into water? The heat of fusion of ice is 1g per 80.0 calories/(gx°C).

Example 2: How much energy is required to vaporize 36.02 grams of water to steam at 100°C? Water’s molar heat of vaporization is 6.01 kJ per mole.

10.0 g H2O x 80.0 calories = 800. calories

1 g H2O

36.02 g H2O x 1 mol H2O x 6.01 kJ = 12.02 kJ

18.01 g H2O 1 mol H2O

Defined: This is the quantity of energy in the form of heat (Q) required to

completely effect a phase change of a unit of mass (m), usually 1kg, of a

substance.

Is this an intensive or extensive property ?

Specific latent heat follows the formula:

Specific Latent Heat (L)

Specific Heat Capacity Calculations

Phase Change Heat Curve for Water

-25

0

25

50

75

100

125

0 20 40 60 80 100 120Joules/Energy --->

Tem

pera

ture

, C

a

b c

d e

f

Specific Heat Capacity:

The amount of energy needed to raise one gram of a substance by 1°C.

Units = J/(gx°C)

Memorize

q = mCΔT

Use q=mC ΔT here

Specific Heat Capacity Calculations

q = mCΔT

q = heat in joules, Jm = mass in gramsC = specific heat capacityΔT = Tfinal – Tinitial

Example 1: A 15 gram sample of water is warmed from 45° to 65°C. The specific heat capacity of water is 4.18 J/(gx°C). How much energy was required to warm the water?

Answer: q = (15)(4.18)(65-45) = (15)(4.18)(20) = 1254 Joules

Example 2: A 2.0 gram sample of metal requires 5.0 Joules of energy to warm from 10 to 20°C. What is the metal’s specific heat capacity?

Answer: 5.0=(2.0)(C)(20-10) or 5.0=(2.0)(C)(10) and C = 0.25 J/(gx°C).

Defined: these are the physical properties of a solution which vary depending on the concentration or ratio of solute particles to the number of solvents in a solution and not on the type of chemical species present

Colligative Properties

Change in Solute ratio induces:

- Vapour pressure lowering

- Boiling Point Elevation

- Freezing Point Depression

- Increase in Osmotic Pressure

Colligative Properties

Adding impurities to a liquid increases the boiling point and decreases the freezing point (widens the liquid temperature range)

Examples:

Adding antifreeze to the water in the radiator to prevent boiling in summer and freezing in winter.

Putting salt on the road to prevent the road from icing up.

NaCl increases water’s boiling point NaCl decreases water’s freezing point NaCl increases water's boiling point

100

105

110

115

120

125

130

0 100 200 300 400

grams of NaCl in 1Liter of water

boi

ling

poin

t, de

gree

s C

NaCl lowers water's freezing point

-30

-25

-20

-15

-10

-5

0

0 100 200 300 400

grams NaCl in 1 L water

Fre

ezi

ng p

oin

t, d

egre

es

C

1. Gases, made up of particles in state of random motion2. Particles move in a straight line until they collide.3. Most of any gas is empty space.4. No Attractive force5. Elastic collisions6. Average kinetic energy, temperature dependent

Kinetic Molecular

Theory

Evidence of Kinetic Theory

DiffusionOsmosis

Diffusion Molecules intermingle as a result of their kinetic

energy of random motion. Consider two containers of gas A & B separated by a partition. The molecules of both gases are in constant motion & make numerous collisions with the partition. If the partition is removed, the gases will mix because of the random velocities of their molecules. In time a uniform mixture of A & B molecules will be produced in the container.

The tendency toward diffusion at room temperature because of the high molecular velocities associated with the thermal energy of the particles.

Diffusion

OsmosisIf two solutions of different concentration are

separated by a semi-permeable membrane which is permeable to the smaller solvent molecules but not to the larger solute molecules, then the solvent will tend to diffuse across the membrane from the less concentrated to the more concentrated solution. This process is called osmosis.

The transport of water & other molecules across cell membranes is essential. The energy which drives the process is usually discussed in terms of osmotic pressure.

Osmosis

• The movement of the solvent• Solute does not move• Involves a semi-permeable

membrane• Usually a passive process

Application to Living Systems

• Think about spending a long day at • the Beach !!