Zumdahl chemistry Ch. 5.4

Question

Given reaction 2NH3(g) + 3Cl2(g)  N2(g) + 6HCl(g), you react 5.0 L of NH3 with 5.0 L of

Cl2 measured at the same conditions in a closed container. Calculate the ratio of pressures in

the container (Pfinal/Pinitial)

Answer 1

2NH₃(g) + 3Cl₂(g) ==> N_2(g) + 6HCl(g) ... balanced equation

Based on the stoichiometry of the balanced equation, Cl2 will be the limiting reactant.

L N2 formed: 5 L Cl2 x 1 L N2 / 3 L Cl2 = 1.67 L N2 formed

L HCl formed: 5 L Cl2 x 6 L HCl / 3 L Cl2 = 10 L HCl

L NH3 used: 5 L Cl2 x 2 L NH3 / 3 L Cl2 = 3.33 L NH3 used

L NH3 remaining = 5 L - 3.33 L = 1.67 L NH3 remaining

L Cl2 remaining = 0

Final volume at end of reaction:

1.67 L + 10 L + 1.67 L = 13.34 L

L are proportional to pressure so

Pfinal = 13.34

Pinitial = 5 + 5 = 10

Pfinal / Pinitial = 13.34 / 10 = 1.3 to 1