At 700 K the equilibrium constant for the water–gas shift reaction CO (g)+ H _ 2 O…
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
At 700 K the equilibrium constant for the water–gas shift reaction
CO(g)+H2O(g)⇌CO2(g)+H2(g)
is Kc=5.0. A 5.00-L reaction vessel at this temperature initially contains
1.00 mol CO,
1.00 mol H2O,
2.24 mol CO2, and
2.24 mol H2.
Assume ideal-gas behavior.
(a) Show that the mixture is at equilibrium before any additional substance is introduced.
(b) Let x be the number of moles of CO injected into the vessel instantaneously (temperature and volume remain constant). Write algebraic expressions for the new concentrations of all four species immediately after the injection, in terms of x.
(c) Determine the smallest value of x (to two significant figures) that will cause the net reaction to proceed in the forward direction after the injection. Show all reasoning, including any inequalities you solve.
(d) Briefly interpret your result from part (c) in the context of industrial operation of reactors that employ this equilibrium.