Thermochemistry

Question 1

Closed System

Answer 1

Exchange energy, but not matter

Question 2

Isolated System

Answer 2

Nothing exchanged

Question 3

Open System

Answer 3

Allows for exchange of energy and matter

Question 4

Isobaric

Answer 4

Constant Pressure

Question 5

Isothermal

Answer 5

Constant temperature (system must gain or lose energy to maintain)

Question 6

Isochoric

Answer 6

Constant Volume, no net pressure-volume work

Question 7

Adiabatic Process

Answer 7

No heat transferred to or from the system by surroundings

Question 8

Heat

Answer 8

Transferrable Energy

q = mcΔt when there is no phase changes

Question 9

Exothermic Reaction

Answer 9

Net release of energy into surroundings (-)

Question 10

Endothermic Reaction

Answer 10

Net absorption of energy from surroundings (+)

Question 11

Enthalpy

Answer 11

Total heat content of a system at a constant pressure (ΔH)

Question 12

Hess’s Law

Answer 12

Enthalpy change of an overall reaction is equal to the sum of the standard heats of formation of the products minus the sum of the standard heats of formation of the reactants
ΔH = ΔH(prod) - ΔH(reac)

Question 13

Entropy

Answer 13

ΔS = q(rev)/ T

Entropy increases during spontaneous reactions

Question 14

Gibbs Free Energy

Answer 14

Energy available in system to do work (ΔG)

Question 15

Gibbs Helmholtz Equation

Answer 15

ΔG = ΔH - TΔS
ΔG = ΔG0 + RT ln Q

Question 16

When will a reaction be spontaneous?

Answer 16

ΔG < 0

Question 17

What happens if ΔG is zero?

Answer 17

ΔG = TΔS

Question 18

What are the only temperature dependent states?

Answer 18

When both ΔH and ΔS have the same sign

Question 19

What happens when ΔH is positive, but ΔS is negative?

Answer 19

The reaction is nonspontaneous at all temperatures

Question 20

What happens when ΔS is positive and ΔH is negative?

Answer 20

The reaction is spontaneous at all temperatures

Question 21

If both ΔH and ΔS are positive?

Answer 21

The reaction is spontaneous only at high temperatures

Question 22

What does the rate of a reaction depend on?

Answer 22

The activation energy, no ΔG

Question 23

Reaction Quotent

Answer 23

ΔG0 = -RT ln K(eq)

Question 24

State Function

Answer 24

Depends only on the initial and final states of a system, not the path

Question 25

Standard Free Energy (ΔG0)

Answer 25

ΔG calculated at 1 atm and 0 K