States of MatterStates of Matter

Chapter 10Chapter 10

Kinetic TheoryKinetic Theory

Kinetic refers to motion.Kinetic refers to motion.

Kinetic energy is the energy of a moving Kinetic energy is the energy of a moving object.object.

Kinetic theory states that the tiny particles Kinetic theory states that the tiny particles in all forms of matter are in constant in all forms of matter are in constant motion.motion.

1.1. A gas is composed of small particles A gas is composed of small particles that have no attractive or repulsive that have no attractive or repulsive forces between them.forces between them.

2.2. Move in constant random motion, but Move in constant random motion, but in straight paths.(Gases fill their in straight paths.(Gases fill their containers regardless of shape or containers regardless of shape or volume. Uncontained gases diffuse volume. Uncontained gases diffuse into space with out limit.)into space with out limit.)

3.3. During collisions kinetic energy is During collisions kinetic energy is transferred without loss from one transferred without loss from one particle to another.particle to another.

Gas PressureGas Pressure

Defined as the force exerted by a gas Defined as the force exerted by a gas per unit surface area of an object.per unit surface area of an object.

VacuumVacuum – empty space, no pressure – empty space, no pressure (outer space)(outer space)

Air exerts pressure on earth because Air exerts pressure on earth because of gravity.of gravity.

Air pressure increases the higher you Air pressure increases the higher you go.go.

The SI unit of pressure is the The SI unit of pressure is the pascal (Pa).pascal (Pa).

mmHg & atmosphere (atm) are mmHg & atmosphere (atm) are other units of pressure.other units of pressure.

1 atm = 760 mmHg = 101.3 kPa1 atm = 760 mmHg = 101.3 kPa

Kinetic Energy & TemperatureKinetic Energy & Temperature

When particles are heated When particles are heated they speed up therefore they speed up therefore increasing temperature.increasing temperature.

GraphsGraphs

Horizontal axis (x-axis) represents the Horizontal axis (x-axis) represents the independent variable.independent variable.

Vertical axis (y-axis) represents the Vertical axis (y-axis) represents the dependent variable.dependent variable.

Range is the minimum and maximum Range is the minimum and maximum values represented in the graph.values represented in the graph.

Making GraphsMaking Graphs

1.1. Choose appropriate rangesChoose appropriate ranges

2.2. The intervals should be convenient The intervals should be convenient numbers (1, 5, 10)numbers (1, 5, 10)

3.3. Draw and label axisDraw and label axis

4.4. Plot dataPlot data

5.5. Connect data with smooth curve. Connect data with smooth curve. (does not have to touch all data (does not have to touch all data points)points)

Nature of LiquidsNature of Liquids

Liquids:Liquids:

1. Particles that make up liquids are in 1. Particles that make up liquids are in motion.motion.

2. Particles have an attractive force 2. Particles have an attractive force between them, but able to move.between them, but able to move.

3. This force is called intermolecular 3. This force is called intermolecular force.force.

Evaporation:Evaporation:conversion to a gas from a liquid that is conversion to a gas from a liquid that is

not boilingnot boiling

1. Vaporization: transition of a liquid to 1. Vaporization: transition of a liquid to gasgas

2. When heat is added vaporization 2. When heat is added vaporization occurs occurs faster.faster.

3. Liquid – vapor (gas)3. Liquid – vapor (gas)

Boiling Points:Boiling Points:The temperature at which the vapor The temperature at which the vapor

pressure of liquid is just equal to the pressure of liquid is just equal to the external pressure.external pressure.

1.1. Boiling points change when external Boiling points change when external pressures change. (less pressure = pressures change. (less pressure = lower boiling points)lower boiling points)

2. The temperature of a boiling liquid 2. The temperature of a boiling liquid never rises above its boiling point.never rises above its boiling point.

Nature of SolidsNature of Solids

Solids:Solids:

1.1. Particles are in fixed points; tend to Particles are in fixed points; tend to vibrate in their spots.vibrate in their spots.

2.2. Particles tend to be in highly organized Particles tend to be in highly organized patterns.patterns.

3.3. Melting point – the temperature at which Melting point – the temperature at which the solid meltsthe solid melts

4.4. As heat is added the organization of As heat is added the organization of particles begins to break down and particles begins to break down and solid melts.solid melts.

5. Melting: Solid – liquid5. Melting: Solid – liquid

Freezing: Liquid – solidFreezing: Liquid – solid

6. Not all solids melt; some decompose6. Not all solids melt; some decompose

Crystal StructuresCrystal Structures

The atoms, molecules or ions are The atoms, molecules or ions are arranged in an orderly, repeating 3-D arranged in an orderly, repeating 3-D pattern.pattern.

Unit CellUnit Cell: smallest group of particles within : smallest group of particles within a crystal; repeating groupa crystal; repeating group

(simple cubic, body centered cubic & (simple cubic, body centered cubic & faceface centered cubic)centered cubic)

..

Crystal StructuresCrystal Structures

1. All crystals have a regular shape.1. All crystals have a regular shape.

2. Crystals have sides or faces.2. Crystals have sides or faces.

3. Crystals are classified in 7 groups3. Crystals are classified in 7 groups

Allotropes:Allotropes:

Two or more different molecular Two or more different molecular forms of the same element in the forms of the same element in the same physical state.same physical state.

Ex. Carbon --- diamond - graphiteEx. Carbon --- diamond - graphite

Amorphous Solids:Amorphous Solids:

Lack an ordered internal structureLack an ordered internal structure

Examples:Examples: Rubber, plastic, Rubber, plastic, asphaltasphalt

Particles are randomly arranged.Particles are randomly arranged.

Change of StateChange of State

Phase Diagram: Phase Diagram: gives the conditions of gives the conditions of temperature & pressure at which a temperature & pressure at which a substance exists as a solid, liquid, & gas.substance exists as a solid, liquid, & gas.

Triple Point:Triple Point: a set of conditions at which a set of conditions at which all three states can exist with one another.all three states can exist with one another.

Sublimation: Sublimation: the change of a the change of a substance from a solid to a vapor substance from a solid to a vapor without passing through the liquid state.without passing through the liquid state.

Examples: Examples:

Solid carbon dioxide (dry ice)Solid carbon dioxide (dry ice)

Moth ballsMoth balls

Add to Gas Pressure:Add to Gas Pressure:

Barometers:Barometers: devices commonly used to devices commonly used to measure atmospheric pressure. This measure atmospheric pressure. This pressure depends on the weather.pressure depends on the weather.

Gas LawsGas Laws

Chapter 12Chapter 12

The SI unit of pressure is the pascal The SI unit of pressure is the pascal (Pa).(Pa).

mmHg & atmosphere (atm) are other mmHg & atmosphere (atm) are other units of pressure.units of pressure.

1 atm = 760 mmHg = 101.3 kPa1 atm = 760 mmHg = 101.3 kPa

REMEMBER:

Properties ofProperties of GasesGases

Compressibility:Compressibility: measure of how much measure of how much the volume of matter decreases under the volume of matter decreases under pressure.pressure.

1.1. Gases are easily compressed.Gases are easily compressed.

2.2. Gases expand to take the shape & Gases expand to take the shape & volume of the container.volume of the container.

3.3. Gas particles are in constant motion.Gas particles are in constant motion.

Variables that describe GasesVariables that describe Gases

1.1. Pressure (P) in kPaPressure (P) in kPa

2.2. Volume (V) in LVolume (V) in L

3.3. Temperature (T) in KTemperature (T) in K

4.4. Moles (n)Moles (n)

Gas PressureGas Pressure

1.1. Increase the # of gas particles; increases Increase the # of gas particles; increases the gas pressurethe gas pressure

2.2. Doubling the # of gas particles; doubles Doubling the # of gas particles; doubles the pressure.the pressure.

3.3. Once the pressure exceeds the strength Once the pressure exceeds the strength of the container the container will of the container the container will rupture.rupture.

(Direct Relationship)(Direct Relationship)

4.4. If you let gas out. Then the pressure If you let gas out. Then the pressure drops.drops.

5.5. When a sealed container of gas under When a sealed container of gas under pressure is opened. Gas inside moves pressure is opened. Gas inside moves from the region of higher pressure to from the region of higher pressure to the region of lower pressure.the region of lower pressure.

Volume: Volume: raise the pressure exerted raise the pressure exerted by contained gas by reducing its by contained gas by reducing its volume.volume.

(Inverse Relationship)(Inverse Relationship)

Temperature: Temperature:

1. Raising the temperature of an 1. Raising the temperature of an enclosed gas increases gas pressure.enclosed gas increases gas pressure.

2. If the temperature doubles then the 2. If the temperature doubles then the pressure doubles.pressure doubles.

(Direct Relationship)(Direct Relationship)

Standard Temperature & Pressure Standard Temperature & Pressure (STP)(STP)

Temperature – 273 KTemperature – 273 K

Volume – 22.4 LVolume – 22.4 L

Pressure – Pressure –

101.3 kpa = 1 atm = 760 mmHg = 760 torr101.3 kpa = 1 atm = 760 mmHg = 760 torr

Boyle’s Law Boyle’s Law

Pressure – Volume RelationshipPressure – Volume Relationship

PP11VV11 = P = P22VV22

Example: Example: A high – altitude balloon contains 30.0 L of A high – altitude balloon contains 30.0 L of helium gas at 103 kPa. What is the helium gas at 103 kPa. What is the volume when the balloon rises to an volume when the balloon rises to an altitude where the pressure is only 25.0 altitude where the pressure is only 25.0 kPa? (Assume STP)kPa? (Assume STP)

PP11 = 103 kPa = 103 kPa VV22 = ? L = ? L

VV11 = 30.0 L = 30.0 L

PP22 = 25.0 kPa = 25.0 kPa

(103 kPa)(30.0 L) = (25.0 kPa)(V(103 kPa)(30.0 L) = (25.0 kPa)(V22))

VV22 = 124 L = 124 L

Charles’s LawCharles’s LawTemperature – Volume RelationshipTemperature – Volume Relationship

VV11 = = VV22

TT11 = T = T22

**Temperature in Kelvin.**Temperature in Kelvin.

Example: Example: A balloon inflated in a room at A balloon inflated in a room at 24 24 ooC has a volume of 4.00 L. The C has a volume of 4.00 L. The balloon is then heated to a balloon is then heated to a temperature of 58 temperature of 58 ooC. What is the new C. What is the new volume if the pressure remains volume if the pressure remains constant?constant?

VV11 = 4.00 L = 4.00 L VV22 = ? L = ? L

TT1 1 = 24 = 24 ooC = 297 KC = 297 K

TT22 = 58 = 58 ooC = 331 KC = 331 K

(4.00L) = V(4.00L) = V22

(297 K)(297 K) (331 K) (331 K)

VV22 = 4.46 L = 4.46 L

Combined Gas LawCombined Gas Law

Combines the 3 gas lawsCombines the 3 gas laws

PP11 V V11 = = PP22 V V22

TT11 = T = T22

Example: Example: The volume of a gas – filled The volume of a gas – filled balloon is 30.0 L at 40 balloon is 30.0 L at 40 ooC and 153 kPa C and 153 kPa pressure. What volume will the balloon pressure. What volume will the balloon have at standard temperature and have at standard temperature and pressure (STP)?pressure (STP)?

VV11 = 30.0 L = 30.0 L VV22 = ? L = ? L

TT11 = 40 = 40 ooC = 313 KC = 313 K

TT22 = 273 K = 273 K

PP1 1 = 153 kPa= 153 kPa

PP22 = 101.3 kPa = 101.3 kPa

(153 kPa)(30.0 L) = (101.3 kPa)(V(153 kPa)(30.0 L) = (101.3 kPa)(V22))

( 313 K )( 313 K ) (273 K ) (273 K )

VV22 = 39.5 L = 39.5 L

Ideal Gas Law (Universal Gas Law)Ideal Gas Law (Universal Gas Law)

Adding # of molesAdding # of moles

PV = nRTPV = nRTP = pressureP = pressureV = volumeV = volumen = # of molesn = # of molesR = ideal gas constant R = ideal gas constant

(8.31 L x kPa / K mole)(8.31 L x kPa / K mole)T = temperatureT = temperature

Example:Example: You fill a rigid steel cylinder that You fill a rigid steel cylinder that has a volume of 20.0 L with nitrogen gas has a volume of 20.0 L with nitrogen gas (N(N22) to a final pressure of 2.00 x 10) to a final pressure of 2.00 x 1044 kPa at kPa at

28 28 ooC. How many moles of NC. How many moles of N22 does the does the

cylinder contain?cylinder contain?

P = 2.00 x 10P = 2.00 x 1044 kPa kPa

n = ? moles of Nn = ? moles of N22

V = 20.0 LV = 20.0 L

T = 28 T = 28 ooCC

(2.00 x 10(2.00 x 1044 kPa)(20.0 L) = n(8.31)(301 K) kPa)(20.0 L) = n(8.31)(301 K)

N = 160 moles NN = 160 moles N22