CHAPTER 13 – States of Matter

THE KINETIC THEORY1.All matter is composed of

very small particles

2.These particles are in constant, random motion

Kinetic Energy and Temperature“KINETIC” from a Greek word meaning “to move.”

Kinetic Energy: Energy of an object in motion

Temperature: A measure of the average kinetic energy of particles

Increase Temperature, ________ Kinetic Energy

Decrease Temperature, _______ Kinetic Energy

IncreaseDecrease

Kinetic Energy of Gas Molecules

m = massv = velocity

**If you increase the temperature, particles move FASTER.

The Four States of Matter

This figure shows the four states of

matter:

_______, ________, ______ and

__________(hydrogen nuclei and

electrons).

Solid Liquid Gas

Plasma

The Four States of MatterSolids: - Have a definite shape and volume

- Particles vibrate about a fixed pointWater is a

solid below 0°C.

The Four States of MatterLiquids:

- Flow, have a definite volume, and take the shape of its container

- Particles are close together, but move randomly

Water is a liquid

between 0°C and 100°C.

The Four States of MatterGases: - Takes the shape and volume of its

container.

- Are highly compressible.

- Have very low densities.

Water is a gas above

100°C.

http://www.youtube.com/watch?v=s-KvoVzukHo

The Four States of MatterPlasma: - The fourth state of matter

- Ionized gas or charged gas particles

- Behaves differently from gases:

(non-elastic collisions, attraction between particles, conducts electricity)

Kinetic Energy and TemperatureIf you continue to reduce temperature, what happens to the kinetic energy?

All particle motion

stops at o K or -273°C.

Absolute zero (0 K, or –273°C)

The temperature at which the motion of particles theoretically stops.

• Particles would have no kinetic energy (or motion).

• Absolute zero has NEVER been produced in the laboratory.

http://www.youtube.com/watch?v=aOa14VQiu3Y

https://www.youtube.com/watch?v=TNUDBdv3jWI

1. Kinetic energy is the energy of ____?An object in motion

2. An increase in temperature increases/decreases the kinetic energy.increases

3. State of matter that has a fixed volume and takes the shape of its container.

Liquid

4. The temperature at which all motion stops?

Absolute Zero

5. The state of matter made of ionized gas particlesPlasma

Temperature Scales

Fahrenheit:• Water freezes at 32˚ F • Water boils at 212˚F

Celsius (or Centigrade):• Based on the freezing (0˚C) and

boiling points (100˚C ) of water.

Temperature ScalesKelvin:

• 0 K is Absolute Zero• No negative values in the Kelvin scale

Temperature Conversions0 K = -273oC

K oC subtract 273 oC K add 273

https://www.youtube.com/watch?v=TNUDBdv3jWI

CHECK: Convert….

1. 86 K to oC

2. 58oC to K

3. 533 K to oC

4. -90oC to K

86 K - 273 = -187oC

58oC + 273 = 331 K

533 K - 273 = 260oC

-90oC + 273 = 183 K

What Causes Pressure of a Gas? Pressure = Force /

Area

• Gas particles exert pressure when they collide with the walls of an object.

Pressure

• Atmospheric pressure is the weight of air per unit of area.

Measuring Pressure• A barometer is the

instrument we use to measure atmospheric pressure

• Atmosphere1.00 atm = 760 mm Hg

Measuring Pressure• A manometer is another instrument used to measure

pressure

1. kilopascals (kPa), 2. millimeters of mercury (mm Hg) 3. torr4. pounds per square inch

(lb/in2 or psi)5. atmosphere (atm)

UNITS OF PRESSURE

Standard Pressure of a Gas

Measured at sea level:

1 atm = 101.3 kPa

= 760 mm Hg

= 760 torr

= 14.7 psi

Pressure Unit Conversions1atm = 760 mmHg = 760 torr = 101.3kPa = 14.7psi

Do the following conversion problems:

1. 1.5 atm = kPa

2. 720 torr = atm

3. 75 kPa = mm Hg

4. 28.14 psi = atm

Standard Temperature and Pressure: STP

• the standard T & P for experimental measurements, to enable comparisons to be made between sets of data usually when working with gases.

Standard temperature is 273 K or 0 °C

Standard pressure is 1 atm or 101.3 kPa

Phase Changes

Courtesy www.lab-initio.com

Energy Change of Phase Changes

solid liquid gas

Exothermic changes (kinetic energy or heat is released)

Endothermic changes (kinetic energy or heat is absorbed)

Deposition

Sublimation

Freezing

Melting

Condensing

Boiling

Energy Change of Phase Changes

solid liquid gas

Exothermic changes (kinetic energy or heat is released or lost)

Endothermic changes (kinetic energy or heat is absorbed or gained)

Lose

Gain

Lose

Gain

Lose

Gain

Chapter 13 Vocabularyso far….

Temperature

Kinetic Energy

Pressure

Absolute Zero

STP (Standard Temperature and Pressure)

MORE Chapter 13 VocabularyExothermic - kinetic energy or heat is released

Endothermic - kinetic energy or heat is absorbed

Normal Boiling Point – temperature at which a substance boils (or condenses) at Standard Pressure (1 atm or 760 mm Hg)

Normal Freezing Point – temperature at which a substance freezes (or melts) at Standard Pressure (1 atm or 760 mm Hg)

Heat Curve of Phase Changeshttp://www.kentchemistry.com/links/Matter/HeatingCurve.htm

HEAT CURVE:Water phase

changes

Temperature remains __________during a phase change.

constant

Phase Diagram

MORE Chapter 13 Vocabulary

Triple Point – T and P at which all three phases (solid, liquid, gas) are present

Critical Point – T and P above which liquid and gas no longer exist as separate phases (above this, it is “supercritical fluid”)

Phase Diagram for Water

CarbonPhase

Diagram for Carbon

Gases – Kinetic Molecular Theory1. All matter is composed of very

small particles

2. These particles are in constant, random motion

3. Collisions between gas particles are perfectly elastic

4. Gas particles are very small and are very far apart.

Kinetic Energy of Gas Molecules

m = massv = velocity

**At any given temperature, the molecules of all gases have the same AVERAGE kinetic energy.

Kinetic Molecular Theory

The average kinetic energy of the molecules is proportional to the absolute temperature.

Kinetic Energy of Gas Molecules

Mixture of He (4 g/mol) and Ne (20 g/mol):

Say the mixture has a KE = 2 J

He: 2 J = 0.5 x (4 g) x (1m/s)2 v = 1 m/sNe: 2 J = 0.5 x (20.2 g) x (0.44m/s)2 v = 0.44 m/s

Bigger gas particles move more __________.

http://www.youtube.com/watch?v=UNn_trajMFo (34 sec)

Slowly

Kinetic-Molecular TheoryLarger molecules (with more mass) move more slowly.

Diffusion of GasesDiffusion is the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout.

Diffusion of GasesDiffusion is the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout.

Kinetic-Molecular TheoryLarger molecules (with more mass) move more slowly.

GRAHAM’S LAW OF DIFFUSIONIf two gases (A and B) are at the same temperature, the molecules have the same average KE.

½ mAvA2 = ½ mBvB

2

rearranging:

GRAHAM’S LAW OF DIFFUSIONThe rate of effusion or diffusion is inversely proportional to the molar mass of the molecule.

Mixture of He (4 g/mol) and Ne (20.2 g/mol):

Which molecule moves faster?

GRAHAM’S LAW OF EFFUSIONExample: What is the ratio of effusion rates for ammonia (NH3) and hydrochloric acid (HCl)?

NH3 (17.0 g/mol) and HCl (36.5 g/mol):

Which molecule moves faster?

GRAHAM’S LAW OF EFFUSION1. Find the ratio of diffusion rates of helium and

chlorine gas:

2. Find the ratio of diffusion rates of oxygen and nitrogen gases:

PressurePressure definition:

Force per unit area

Dalton’s Law of Partial PressuresIn a mixture of gases, the total pressure is the sum of

the partial pressures of the component gases.

Dalton’s Law – Partial Pressures• The contribution each gas in a mixture makes to the total

pressure is called the partial pressure exerted by that gas.

Ptotal = PA + PB + PC

Ptotal = 100 kPa + 250 kPa + 200 kPa

Ptotal = 550 kPa

Dalton’s Law – Another ProblemA gas mixture containing oxygen, nitrogen, and carbon dioxide has a total pressure of 32.9 kPa. If PO2 = 6.6 kPa and PN2 = 23.0 kPa, what is PCO2?

Ptotal = PO2 + PN2 + PCO2

32.9 kPa = 6.6 kPa + 23.0 kPa + PCO2

PCO2 = 32.9 kPa – (6.6 kPa + 23.0 kPa) = 3.3 kPa

Real Gases

In the real world, the behavior of gases only conforms to the ideal-gas equation at relatively high temperature and low pressure.

Deviations from Ideal Behavior

The assumptions made in the kinetic-molecular model break down at high pressure and/or low temperature.

Deviations from Ideal Behavior

NEED TO ADD – MORE DEVIATION FOR LARGE? MOLECULES AND POLAR MOLECULES

Avogadro’s Principle• Use for gas stoichiometry problems – • “Liter to Liter” conversions

Liter-Liter Conversions - Example

What is the total number of liters of NO(g) produced when 1.6 liters of O2 reacts completely with nitrogen at constant temperature and pressure?

N2 (g) + O2 (g) 2 NO (g)

Given (L of the known) # liters unknown= calculated L of unknown

# liters known

GIVENMOLE RATIO FROM BALANCED

CHEM EQN

1.6 L O2 2 L NO= 3.2 L NO

1 L O2

Liter-Liter Conversions - Example

If I have 13 L of N2 and excess H2, how many liters of NH3 can I make at constant temperature and pressure?

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

Given (L of the known) # liters unknown= calculated L of unknown

# liters known

GIVENMOLE RATIO FROM BALANCED

CHEM EQN

13 L N2 2 L NH3= 26 L NH3

1 L N2