For the reaction CH4(g) + 2O2(g)CO2(g) + 2H2O(g) H° = -802.3 kJ and S° = -5.2 J/K

Question

For the reaction

CH₄(g) + 2O₂(g)CO₂(g) + 2H₂O(g)

H° = -802.3 kJ and S° = -5.2 J/K

The maximum amount of work that could be done when 2.25 moles of CH₄(g)react at 322 K, 1 atm is _____ kJ.

Assume that H° and S° are independent of temperature.

Answer 1

∆Hrxn = -802.3 kJ/mol x 2.25 moles = -1805 kJ

∆Srxn = -0.0052 kJ/mol/K x 2.25 moles = -0.0117 kJ/K

T = 322K

∆G = ∆H - T∆S

∆G = -1805 kJ - (322K)(-0.0117 kJ/K) = -1805 kJ + 3.764 kJ

∆G = -1801 kJ (non-expansion work)