Question

When propanol (CH3CH2CH2OH) is combusted, such as when in a gasoline blend, the following reaction occurs:

2CH3CH2CH2OH(l)+9O2(g)?6CO2(g)+8H2O(g)
Based on the standard free energies of formation given in the table below, what is the standard free energy change for this reaction?
Substance ?G?f
(kJ/mol)
CH3CH2CH2OH(l) ?360.5
O2(g) 0
CO2(g) ?394.4
H2O(g) ?228.6
Express your answer to one decimal place and include the appropriate units.

Answer 1

Answer: -3474.2 kJ

Explanation:

2CH3CH2CH2OH(l)+9O2(g)→6CO2(g)+8H2O(g)

ΔG∘ = Products - reactants

Products: 6CO2(g)+8H2O(g)

Reactants: 2CH3CH2CH2OH(l)+9O2(g)

6 * −394.4 = -2366.4

8 * - −228.6 = -1828.8

-2366.4 + -1828.8 = -4195.2

2 * −360.5 = -721

9 * 0 = 0

-721 + 0 = -721

ΔG∘ = (-4195.2) - (-721) = -3474.2 kJ