Question

1.
For the reaction

2SO₂(g) + O₂(g) ----->2SO₃(g)

ΔG° = -148.8 kJ and ΔS° = -187.9 J/K at 261 K and 1 atm.

The maximum amount of work that could be done by this reaction when 1.98 moles of SO₂(g) react at standard conditions at this temperature is _______ kJ.

2. For the reaction

2Na(s) + 2H₂O(l) ---->2NaOH(aq) + H₂(g)

ΔH° = -368.6 kJ and ΔS° = -15.3 J/K

The maximum amount of work that could be done when 2.25 moles of Na(s) react at 341 K, 1 atm is ________ kJ.

Assume that ΔH° and ΔS° are independent of temperature.

Answer 1

Q1. 2 SO₂ (g) + O₂ (g) 2 SO₃ (g)

maximum amount of work = 147.3 kJ

Q2. 2 Na (s) + 2 H₂O (l) 2 NaOH (aq) + H₂ (g)

maximum amount of work = 408.8 kJ

Explanation

Q1. Given : G^o = -148.8 kJ

moles SO₂ = 1.98 mol

maximum amount of work = -(G^o) * (moles SO₂)

maximum amount of work = -(-148.8 kJ / 2 mol SO₂) * (1.98 mol)

maximum amount of work = 147.3 kJ