Question

The Reaction Quotient

Part B

The following reaction was carried out in a 3.25 L reaction vessel at 1100 K :

C(s)+H2O(g)⇌CO(g)+H2(g)

If during the course of the reaction, the vessel is found to contain 9.25 mol of C , 14.6 mol of H2O , 3.40 mol of CO , and 8.20 mol of H2 , what is the reaction quotient Q ?

Enter the reaction quotient numerically.

Q=???

Answer 1

Ans. Calculate the concentrations in terms of molarity.

Molarity of H2O = number of moles / Volume of vessel

                        = 14.6 mol/ 3.25 L = 4.492 mol/ M = 4.492 M

Molarity of CO = 3.40 mol/ 3.25 L = 1.046 M

Molarity of H2 = 8.20 mol/ 3.25 L = 2.523 M

Now,

Reaction quotient, Q = ([CO] [H2]) / ([C] [H2O])

Or, Q = (1.046 x 2.523) / (4.492) = 0.588

Thus, Q = 0.588 for the given reaction.

Note: [C] is excluded from the expression because activity of solids is taken unity.