Unit 10 Vocab

Question 1

• based on the idea that particles of matter are always in motion.
• Developed by scientists in the late 19th century to describe behavior of molecules and atoms that make up matter
• Used to explain properties of solids, liquids, and gases

Answer 1

kinetic-molecular theory

Question 2

a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory

Answer 2

ideal gas

Question 3

a collision in which there is no net loss of total kinetic energy (happens between gas particles and container walls as well as other gas particles)

Answer 3

elastic collision

Question 4

the movement of particles from regions of higher density to lower density (the particles spread out spontaneously and mix)

Answer 4

diffusion

Question 5

a process by which gas particles pass through a tiny opening

Answer 5

effusion

Question 6

a gas that does not behave completely according to the assumptions of the kinetic-molecular theory

Answer 6

real gas

Question 7

a substance that can flow and therefore take the shape of its container(applies to liquids and gases)

Answer 7

fluids

Question 8

a force that tends to pull adjacent parts of a liquid’s surface together, thereby decreasing surface area to the smallest possible size. (a property common of all liquids)

Answer 8

surface tension

Question 9

the attraction of the surface of a liquid to the surface of a solid (ex. liquid going up a test tube)

Answer 9

capillary action

Question 10

the process by which a liquid or solid changes into a gas

Answer 10

vaporization

Question 11

the process by which particles escape from the surface of a non-boiling liquid and enter the gas state (a form of vaporization)

Answer 11

evaporation

Question 12

the physical change of a liquid to a solid by removal of energy as heat

Answer 12

freezing

Question 13

solids composed of crystals (most solids are this)

Answer 13

crystalline solids

Question 14

a substance in which the particles are arranged in an orderly, geometric, repeating pattern

Answer 14

crystal

Question 15

a solid in which the particles are arranged randomly (noncrystalline solids: glass, plastics, etc.)

Answer 15

amorphous solid

Question 16

-the physical change of a solid to a liquid by the addition of energy as heat

Answer 16

melting

Question 17

the temperature at which a solid becomes a liquid

Answer 17

melting point

Question 18

– substances that retain certain liquid properties even at temperatures which they appear to be solid (a property of amorphous solids since they can flow over a wide range of temps.)

Answer 18

supercooled liquids

Question 19

the total three-dimensional arrangement of particles of a crystal

Answer 19

crystal structure

Question 20

the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice

Answer 20

unit cell

Question 21

any part of a system that has uniform composition and properties

Answer 21

phase

Question 22

the process by which a gas changes into a liquid

Answer 22

condensation

Question 23

a dynamic condition in which two opposing changes occur at equal rates in a closed system(ie. an equal amount of molecules moving from liquid to vapor phase and vise-versa in a closed container)

Answer 23

equilibrium

Question 24

the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature

Answer 24

equilibrium vapor pressure

Question 25

liquids that evaporate readily

Answer 25

volatile liquids

Question 26

the conversion of a liquid to a vapor within the liquid as well as at its surface

Answer 26

boiling

Question 27

the temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure

Answer 27

boiling point

Question 28

the amount of energy as heat that is needed to vaporize one mole of liquid at the liquid’s boiling point at the constant pressure (∆H_v)

Answer 28

molar enthalpy of vaporization

Question 29

– the temperature at which the solid and the liquid are in equilibrium at 1 atm (760 torr, or 101.3 kPa) pressure

Answer 29

freezing point

Question 30

the amount of energy as heat required to melt one mole of solid at the solid’s melting point (∆H_f)

Answer 30

molar enthalpy of fusion

Question 31

the change of state from a solid directly to a gas

Answer 31

sublimation

Question 32

the change of state from a gas directly into a solid

Answer 32

deposition

Question 33

a graph of pressure versus temperature that shows the conditions under which the phases of a substance can exist

Answer 33

phase diagram

Question 34

indicates the temperature and pressure conditions at which the solid, liquid, and vapor of the substance can coexist at equilibrium.

Answer 34

triple point

Question 35

indicates the critical temperature and critical pressure

Answer 35

critical point

Question 36

indicates the critical temperature and critical pressure

Answer 36

critical point

Question 37

the temperature above which the substance cannot exist in the liquid state

Answer 37

critical temperature (tc)

Question 38

the lowest pressure at which the substance can exist as a liquid at the critical temperature

Answer 38

critical pressure (Pc)