Consider the reaction SO2(g) + 2C(s,graphite) ---> S(s,rhombic) + 2CO(g) for which H° = 75.80 kJ and S° = 167.6 J/K at 298.15 K.

Question

Consider the reaction SO2(g) + 2C(s,graphite) ---> S(s,rhombic) + 2CO(g) for which H° = 75.80 kJ and S° = 167.6 J/K at 298.15 K.

(1) Calculate the entropy change of the UNIVERSE when 1.860 moles of SO₂(g) react under standard conditions at 298.15 K.

S_universe =  ___ J/K

(2) Is this reaction reactant or product favored under standard conditions?

(3) If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction is reactant favored, choose 'reactant favored'.

Answer 1

Molar mass SO₂ = 64.06 g/mol

1.860 g x 1 mole/64.06 g = 0.1561 moles

ΔS_univ = 0.1561 moles x 167.6 Jmol^-1K^-1= 26.16 J/K

ΔG = ΔH - TΔS = 75.80 kJ - (298.15K)(0.1676 kJ/K)

ΔG = 75.80 - 49.97 = 25.83 kJ

Since ΔG is positive, the reaction is NOT spontaneous and therefore is reactant favored.