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29 terms

Combustion reactions are ________.

Spontaneous

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

Negative, Positive.

When a reaction goes from two moles of a gas to one mole of a solid the delta S (of the system) is expected to be ________.

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

Gibbs Free Energy Equation is _______. (standard equation)

∆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.

Dissolving _______ dissolves spontaneously in water, yet is endothermic.

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.

∆S = ____

q(rev) / T

Statistical Thermodynamics defines entropy as the available ________ for a given reaction.

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.

.....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)

∆G° = ________. (equilibrium equation)

-RT ln K

"Free" Energy means ______.

The maximum energy available to do useful work.

If Q < K, the reaction must proceed ______ to achieve equilibrium.

Forward

If Q > K, the reaction must proceed ______ to achieve equilibrium.

Backwards

At equilibrium ∆G = __. Why?

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

In a product-favored reaction, the equilibrium position occurs closer to the ______ side.

Reactant

In a reactant-favored reaction, the equilibrium position occurs closer to the ______ side.

Product

Q is the _____ .

Reaction Quotient

A process that is entropy-favored and enthalpy-disfavored occurs when _____ and _____.

∆S° > 0, ∆H° > 0

A process that is entropy-disfavored and enthalpy-favored occurs when _____ and _____.

∆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