Barium carbonate decomposes when heated.

BaCO₃(s) → BaO(s) + CO₂(g)

a. Use your knowledge of Hess cycles from Chapter 6 to calculate the enthalpy change of this reaction. Express your answer to three significant figures.

ΔH^θ_f [BaCO₃(s)] = –1216.0 kJ mol^–1

ΔH^θ_f[BaO(s)] = –553.5 kJ mol^–1

ΔH^θ_f[CO₂(g)] = –393.5 kJ mol^–1

b. Use your answer to part a and the data below to calculate ΔStotal for this reaction under standard conditions. Express your answer to three significant figures..

ΔS^θ[BaCO₃(s)] = +112.1 J K^–1 mol^–1

ΔS^θ[BaO(s)] = +70.40 J K^–1 mo^l–1

ΔS^θ[CO₂(g)] = +213.6 J K^–1 mol^–1

c. Is this reaction spontaneous (feasible) at 298 K? Explain your answer.

d. i. Calculate the temperature at which this reaction has a total entropy value of zero.

ii. What main assumption did you make in your calculation in part d i?