Thermochemistry and Phase Changes

Question 1

Gibbs free energy

Answer 1

deltaG=deltaH-TdeltaS

deltaG= -RT lnKeq

Question 2

bond breakage

Answer 2

endothermic

Question 3

bond formation

Answer 3

exothermic

Question 4

entropy (S)

Answer 4

• measure of disorder/randomness

- increases from solid to liquid to gas

Question 5

boiling point

Answer 5

-more polar, stronger interactions, higher bp
-hydrogen bonding, stronger int, higher bp
-higher vapor pressure, higher bp
-

Question 6

gas to solid

Answer 6

deposition

Question 7

solid to gas

Answer 7

sublimation

Question 8

liquid to solid

Answer 8

fusion/melting

Question 9

solid to liquid

Answer 9

freezing

Question 10

liquid to gas

Answer 10

vaporization

Question 11

gas to liquid

Answer 11

condensation

Question 12

first law of thermodynamics

Answer 12

• change in internal energy of a system is the sum of the change in heat and the work for that system
• deltaU = Q - W

Question 13

second law of thermodynamics

Answer 13

all spontaneous processes in an isolated system lead to an increase in entropy

Question 14

isothermal process

Answer 14

• when pressure of a gas increases, the volume decrease and visa versa
• U=0 is gas is ideal (W=Q)

Question 15

isobaric process

Answer 15

• when the volume of a system increases its temperature will increase as well
• W = PdeltaV

Question 16

isovolumetric process

Answer 16

• volume remains constant
• work done = 0
• deltaU = Q

Question 17

adiabatic expansion or compression

Answer 17

• no heat is transferred
• change in internal energy is opposite of work done by the system
• deltaU = -W

Question 18

open system

Answer 18

can exchange energy and matter with the environment

Question 19

closed system

Answer 19

can exchange energy but NOT matter with the environment

Question 20

isolated system

Answer 20

CANNOT exchange energy or matter with the environment