Chapter 13/14

Question 1

Kinetic molecular theory

Answer 1

1. The particles in a gas are considered to be small spheres with insignificant volume
   - empty space between gas particles
   - no attractive/repulsive forces between particles
2. Motion of particles in a gas is rapid, constant, and random
3. All collisions between gas particles are perfectly elastic
   - kinetic energy is transferred between particles

Question 2

Kinetic theory

Answer 2

All matter consists of tiny particles that are in constant motion

Question 3

gas pressure

Answer 3

• from the force exerted by a gas per unit surface area of an object
• result of simultaneous collisions of billions of rapidly moving particles

Question 4

atmopsheric pressure

Answer 4

• results from the collisions of atoms and molecules in air

- increased elevation=decreased atmospheric pressure

Question 5

kinetic energy and temperature

Answer 5

• as a substance is heated, the particles absorb energy
• some energy is stored as potential energy, which does not affect temperature
• some energy speeds up the particles, which causes a temperature increase

Question 6

kinetic theory for liquids

Answer 6

-particles have kinetic energy, but the particles in a liquid are attracted to one another - gives liquids a definite volume

Question 7

evaporation

Answer 7

• change from a liquid to a gas
• particles must have enough kinetic energy to overcome the attractive forces between the particles
• evap. occurs faster at warmer temperatures

Question 8

vapor pressure

Answer 8

-a measure of the force exerted by a gas above a liquid
-over time, the number of particles evaporating into the gas phase will reach a point where particles start to condense back into the liquid phase
rate of evaporation=rate of condensation
—–dynamic equilibrium established

Question 9

allotropes

Answer 9

two or more different molecular forms of the same element in the same physical state
ex: carbon - diamond, graphite, fulleren

Question 10

amorphous solids

Answer 10

not all solids are crystalline, some lack an ordered internal structure (randomny arranged particles, irregular fracture patterns)

Question 11

depostion

Answer 11

gas to solid

Question 12

sublimation

Answer 12

solid to gas

Question 13

volume

Answer 13

• volume and pressure have an indirect relationship
• pressure increases when volume decreases bc there is less space for the particles to move, so there are more collisions

Question 14

temperature

Answer 14

• temperature and pressure have a direct relationship
• pressure increases when temperature increases - as temp increases, so does kinetic energy- move quicker and collide more often

Question 15

boyles law

Answer 15

PRESSURE AND VOLUME
-the pressure of a gas depends on how often the particles strike the walls of the container
-temp is constant
P1V1=P2V2

Question 16

charles law

Answer 16

-volume is directly proportional to temperature
-pressure is constant
V1/T1=V2T2

Question 17

gay-lussacs law

Answer 17

-deals with pressure and temperature
-pressure is directly proportional to temperature
-volume is constant
P1/T1=P2/T2

Question 18

combined gas law

Answer 18

combination of boyles, charles, and gay-lussacs laws
-number of particles is constant
-all units must be consisten
P1V1/T1=P2V2/T2

Question 19

ideal gases vs. real gases

Answer 19

• ideal gases follow the gas laws at all temperature and pressure conditions
• ideal gases conform completely to each KMT assumption
• real gases behave very much like an ideal gas at most conditions of pressure and temperature

Question 20

conditions for an ideal gas

Answer 20

• most gases, ideal and real, are at conditions of high temperature and low pressure
• real gases differ from true ideal gases at conditions of low temperature and high pressure
  
  • slow moving, particles close together

Question 21

ideal gas law

Answer 21

deals with pressure, volume, temperautre, moles, and a gas constant
PV=nRT

Question 22

ideal gas constant

Answer 22

symbol: R
8.31 l-kPa/mol-K
.0821 L-atm/mol-k

Question 23

partial pressure

Answer 23

the contribution that each gas in a mixtures makes to the total pressure of the gas

Question 24

dalton’s law of partial pressures

Answer 24

mathematical expression that states that at a constant volume and temp., the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases

Question 25

effusion

Answer 25

the process by which a gas escapes through a small hole

Question 26

diffusion

Answer 26

the spreading and mixing of gas particles from high concentration to low concentration until particles are uniform

Question 27

grahams law

Answer 27

-relates to rate of diffusion or effusion of a gas to its molar mass
Rate A/Rate B=sq. rt. mm B/mm A
-states that the rate at which a gas will effuse or diffuse is inversely proportional to the sq. r. of the molar masses of the gases
-lighter gases will travel faster than heavier ones