Sulfur dioxide reacts with oxygen to form sulfur trioxide.
2SO2(g) + O2 (g) ⇌ 2SO3 (g) ΔrH = -288.4 kJ mol−1
The standard molar entropy values at 298 K are given in the table.
|
SO2 (g) |
O2 (g) |
SO3 (g) |
/ J K−1mol−1 |
+248.1 |
+205.0 |
+95.6 |
i)
Calculate the entropy change of the system, ΔSsystem, for the forward reaction.
Include a sign and units in your answer.
2SO2 (g) + O2( g) → 2SO3 (g)
(2)
ii)
Calculate the free energy change, ΔG, at 298 K and hence deduce whether the reaction is feasible.
(3)
iii)
In industry, the reaction is carried out at about 700 K using a vanadium(V) oxide catalyst.
Calculate the value of the equilibrium constant, K, at 700 K.
ΔG at 700K is -60 kJ mol−1
(3)
iv)
The equilibrium constant has a larger value at 298 K than at 700K.
Explain why the reaction is carried out at 700 K and not at 298 K.
(2)