Thermodynamics

Question 1

Heat

Answer 1

Thermal kinetic energy from the random motion of particles

Question 2

Exothermic

Answer 2

Heat goes from the system to the surroundings; heat is “released” (-)

Question 3

Endothermic

Answer 3

Heat goes from surroundings to system; heat is “absorbed” (+)

Question 4

Spontaneity

Answer 4

Whether or not a process occurs under a given set of conditions without a driving force

Question 5

Entropy

Answer 5

Energy dispersion disorder (number of microstates).

Question 6

The second law of Thermodynamics

Answer 6

For a process to be spontaneous entropy in the universe must increase

Question 7

What is the entropy order for s, l, and g

Answer 7

(s)<(l)«<(g)

Question 8

What causes entropy to increase

Answer 8

Increase in temperature, higher the molecular complexity, increase in molar mass, the more something can move around, increase in moles of gas, and the higher the number of particles

Question 9

Spontaneous

Answer 9

Occurs as written

Question 10

What are the rules to determine entropy in aqueous solutions

Answer 10

The smaller the charge of the solute, the more entropy increases

Question 11

Why do smaller charges cause entropy to increase

Answer 11

Higher charged ions cause more order in the solution so the entropy decreases

Question 12

How do you calculate entropy

Answer 12

Δ G rxn = ΔG (products) - ΔG (reactants)

Question 13

Third Law of Thermodynamics

Answer 13

For a pure crystalline substance at absolute zero (0 K), entropy equals 0

Question 14

How do you get the Δ S surroundings?

Answer 14

ΔS = - ΔH/temp

Question 15

Gibbs free energy

Answer 15

Energy available to do something or energy needed to do something (in kj/mol)

Question 16

What does it mean if G is (+/-)

Answer 16

-G: spontaneous
+G: nonspontaneous

Question 17

How to determine G when given the values?

Answer 17

ΔG = G (products) - G ( reactants)

Question 18

G formula

Answer 18

ΔGrxn = ΔHrxn - T x Srxn

Question 19

How do you determine ΔG if you are given observations?

Answer 19

(+)   -   (-)  = always (-)
(-)    -   (+) = always (+)
(+)   -   (+)  = depends; as T rises, G becomes negative
(-)    -   (-) = depends; as T rises, G becomes positive

Question 20

Gibbs free energy formula without standard G

Answer 20

ΔG = -RTln(K)

Question 21

How to get quotient K/Q?

Answer 21

[products]
—————- (only gas or aqueous included)
[reactants]

Question 22

Equilibrium rules

Answer 22

Q = K: at equilibrium
Q > K: too many products; reaction must proceed in reverse
Q < K: too few products; reaction must go forward