29 terms

# Enthalpy Entropy and Free Energy Exam

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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.
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