SL Paper 2

Consider the following equilibrium:

4NH3(g)+5O2(g)4NO(g)+6H2O(g)ΔHΘ=909 kJ

Nitrogen reacts with hydrogen to form ammonia in the Haber process, according to the following equilibrium.

N2(g)+3H2(g)2NH3(g)ΔHΘ=92.6 kJ

Deduce the equilibrium constant expression, Kc, for the reaction.

[1]
a.i.

Predict the direction in which the equilibrium will shift when the following changes occur.

The volume increases.

The temperature decreases.

H2O(g) is removed from the system.

A catalyst is added to the reaction mixture.

[4]
a.ii.

Define the term activation energy, Ea.

[1]
b.

Nitrogen monoxide, NO, is involved in the decomposition of ozone according to the following mechanism.

O3O2+OO3+NONO2+O2NO2+ONO+O2Overall:2O33O2

State and explain whether or not NO is acting as a catalyst.

[2]
c.

Define the term endothermic reaction.

[1]
d.i.

Sketch the Maxwell-Boltzmann energy distribution curve for a reaction with and without a catalyst, and label both axes.

[3]
d.ii.

Define the term rate of reaction.

[1]
e.i.

Iron, used as the catalyst in the Haber process, has a specific heat capacity of 0.4490 Jg1K1. If 245.0 kJ of heat is supplied to 8.500 kg of iron, initially at a temperature of 15.25 °C, determine its final temperature in K.

[3]
f.