Answer to Question #155150 in General Chemistry for Alex

Question

Calculate the entropy (∆S) for the following reaction:

1) H2O (g) + CO (g) = CO2 (g) + H2 (g)

2) C2H2 (g.) + 5 / 2O2 (g.) → 2CO2 (g.) + H2O (l.)

Answer 1

1. [1ΔSf(H2 (g)) + 1ΔSf(CO2 (g))] - [1ΔSf(H2O (g)) + 1ΔSf(CO (g))]

[1(130.59) + 1(213.68)] - [1(188.72) + 1(197.9)] = -42.35 J/K

-42.35 J/K     (decrease in entropy)

2. C2H2 + 5/2 O2 -> 2CO2 + H2O Entropy = -1299.6 kJ C + O2 -> CO2 Entropy = -393.5 kJ H2 + 1/2 O2 -> H2O Entropy = -285.8 kJ