Phase Changes and Phase Diagrams

Question 1

when a substance changes from solid to liquid to gas, the molecules -

Answer 1

remain intact

Question 2

changes in state are due to changes in the - rather than in those - the molecules

Answer 2

forces among molecules, within

Question 3

a phase change can either be - or -

Answer 3

exothermic, endothermic

Question 4

in this change, heat is released

Answer 4

exothermic change

Question 5

in this change, heat is absorbed

Answer 5

endothermic change

Question 6

exothermic changes

Answer 6

freezing, condensation, deposition

Question 7

endothermic changes

Answer 7

melting, evaporation, sublimation

Question 8

a graphical representation of the pressure-temperature relationships that apply to the equilibria between the phases of s substance

Answer 8

phase diagram

Question 9

a graphical way to summarize the conditions under which equilibrium exists between different states of matter

Answer 9

phase diagram

Question 10

allows you to predict the phase of a substance that is stable at a given temperature and pressure

Answer 10

phase diagram

Question 11

the end point of a phase equilibrium curve. the end point of the pressure-temperature curve that designates conditions under which a liquid and its vapor can coexist

Answer 11

critical point

Question 12

the temperature and pressure at which solid, liquid, and gas phase of a matter coexist in equilibrium

Answer 12

triple point

Question 13

• is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist

Answer 13

superficial fluod

Question 14

in phase diagrams of substances other thsn water, the slope of the solid liquid line slopes - (-)

Answer 14

forward (positive)

Question 15

in the phase diagram of water, the slope of the solid-liquid line slopes - (-)

Answer 15

downward (negative)