We’re being asked to determine the if the reaction proceed spontaneously as written at 452 K when the partial pressures of each of the three species are 0.25 atm.
(CH3)2CHOH(g) ⇋ (CH3)2CO(g) + H2(g)
Recall that if:
• ΔG < 0 or ΔG = (–); the reaction is spontaneous
• ΔG = 0; the reaction is at equilibrium
• ΔG > 0 or ΔG = (+); the reaction is non-spontaneous
Recall that ΔG˚rxn and K are related to each other:
When the system is not at equilibrium the equation of Gibbs Free energy changes to:
For this problem, we need to do the following steps:
Step 1: Calculate for ΔG˚rxn at 452 K
Step 2: Calculate for Q
Step 3: Calculate ΔGrxn.
The decomposition of isopropanol to form acetone and hydrogen gas (reaction shown below) has an equilibrium constant of 0.44 at 452 K. Assume ΔH° and ΔS° are temperature-independent.
(CH3)2CHOH (g) ⇋ (CH3)2CO (g) + H2 (g)
Useful data (at 298 K):
(CH3)2CHOH (g) ΔH°f = -261.1 kJ/mol
(CH3)2CO (g) ΔH°f = -218.5 kJ/mol
Will the reaction proceed spontaneously as written at 452 K when the partial pressures of each of the three species are 0.25 atm? Justify your answer with appropriate calculations.
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