# Enthalpy Entropy and Free Energy Exam

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Spontaneous

### When a reaction is said to be exothermic delta H is ________ and delta S (of the surroundings) is ________.

Negative, Positive.

Negative

### When a reaction is exothermic and the entropy is increasing, it is a __________ reaction at ____ temp(s). This is a type __ reaction.

Spontaneous, All, 1

### When a reaction is exothermic and the entropy is decreasing, it is a __________ reaction at ____ temp(s). This is a type __ reaction.

Spontaneous, Low, 2

### When a reaction is endothermic and the entropy is increasing, it is a __________ reaction at ____ temp(s). This is a type __ reaction.

Spontaneous, High, 3

### When a reaction is endothermic and the entropy is decreasing, it is a __________ reaction at ____ temp(s). This is a type __ reaction.

Non-Spontaneous, All, 4

∆G = ∆H - T∆S

### Gibbs Free Energy Equation is _______. (expressed in terms of entropy only).

-T∆S(universe) = ∆H(system) - T∆S(system)

### Spontaneous changes ________. (finish definition)

Occur only in the direction that leads to equilibrium, naturally and unaided.

NH₄NO₃

### The 1st law of thermodynamics states that _______.

In any process energy must be conserved.

### The 2nd law of thermodynamics states that ______.

A spontaneous process is one that results in an increase of the entropy of the universe.

q(rev) / T

Microstates

### Entropy explains that energy goes from more ______ to more ______.

Concentrated, Dispersed

### S =

k ln W
.....where k is the proportionality (Boltzmann's) constant and W is the number of accessible microstates.

### The 3rd law of thermodynamics states that ______.

A perfect crystal at 0 K has zero entropy. (S = 0)

-RT ln K

### "Free" Energy means ______.

The maximum energy available to do useful work.

Forward

Backwards

### At equilibrium ∆G = __. Why?

0, because a reaction proceeds spontaneously toward the minimum in free energy, which corresponds to equilibrium.

Reactant

Product

### Q is the _____ .

Reaction Quotient

∆S° > 0, ∆H° > 0

∆S° < 0, ∆H° < 0

### Equation _____ relates the free energy change under nonstandard conditions (∆G) to the standard free energy change (∆G°) and the reaction quotient Q.

∆G = ∆G° + RT lnQ

Example: