Question

Consider the decomposition of nitrous oxide, laughing gas, 2 N2O (g) = 2 N2(g) + O2(g)

At 25⁰C, Kc is 7.3 x 1034

(a) Based on the information given, what can you say about the rate of decomposition of the reaction?

(b) Based on the information given, does nitrous oxide have a tendency to decompose into nitrogen gas and oxygen?

(c) What is the Kp for the reaction at 25⁰C?

Answer 1

(a) Given that; At 25⁰C, Kc is 7.3 x 1034

Not concentration and time given; based on this information only we cannot predict the rate of decomposition of of nitrous oxide, laughing gas, 2 N2O (g).

(b) See here the value of At 25⁰C, Kc is 7.3 x 1034 which is very high. This indicates the nitrous oxide has a strong tendency to decompose into nitrogen and oxygen.

(c)

At 25⁰C, Kc is 7.3 x 1034

Kp = Kc(RT)^Dn

Kp = equilibrium constant in terms of partial pressures (atm)
Kc = equilibrium constant in terms of concentrations(molarity)
R = ideal gas constant ( 0.082 atm.L / K.mol)
T = absolute temperature (25°C = 298K)
Δn = Σ n products - Σ n reactants
Δn = (3) - (2) = 1

Kp = 7.3 x 10^34 (0.082 atm.L / K.mol *298 K)¹

= 1.8 x 10^36