Chemistry Problem Solving Videos @ WVU

Chem 116 - General Chemistry II

Gibbs Free Energy, Spontaneity, and Equilibrium

Reaction Spontaneity and Temperature

A certain reaction is exothermic and entropy decreases on going from reactants to products. Discuss the spontaneity of this reaction at different temperatures.

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Calculating the Gibbs Free Energy Change I

Calculate the standard Gibbs free energy change (ΔG˚) at 25˚C for the reaction below.
2 W(s) + 3 O2(g) ≡ 2 WO3(s)   ΔH˚=-1686 kJ

At 25˚C, is this reaction spontaneous or nonspontaneous?

At what temperature will this reaction change in spontaneity?

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Calculating the Gibbs Free Energy Change II

Consider the reaction shown below and the conditions p(O3) = 2.0 atm and p(O2) = 2.0 atm. Under these non-standard conditions, the numerical value of ΔG at 25˚C is ___________.

2 O3(g) ≡ 3 O2(g)
ΔGf˚ O3 = 163 kJ/mol

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Determining the Numberical Value of K

Consider the reaction for conversion of graphite to diamond:
C(s, graphite) ≡ C(s, diamond)   ΔG˚= 2.9 kJ/mol at 25 °C

At 25˚C, what is the numerical value of K for this conversion?

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