Dynamic Equilibria Practice Questions

Write the equation, including state symbols, for the reversible reaction between nitrogen and hydrogen to form ammonia.

The nitrogen used in the Haber process is obtained from the air.

State the raw material from which the hydrogen is obtained, and give one reason why air is a suitable source of nitrogen.

Fertilisers contain compounds of three elements. Name these three elements.

Ammonium nitrate is a fertiliser made from ammonia and nitric acid.

Write the balanced equation for this reaction.

Name the type of chemical reaction that takes place between ammonia and nitric acid.

Ammonium nitrate is very soluble in water. Suggest why this is an advantage when it is used as a fertiliser.

State and explain the effect of increasing the pressure on the rate at which equilibrium is reached.

The manufacturer increases the concentration of hydrogen in the reaction mixture. State the effect this has on the rate at which equilibrium is reached.

Explain the effect on the rate at which equilibrium is reached if the temperature is lowered from $250\,^{\circ}\mathrm{C}$ to $150\,^{\circ}\mathrm{C}$.

State the effect of the copper and zinc oxide catalyst on the equilibrium yield of methanol.

State which curve, A or B, was obtained in the experiment using the platinum catalyst. Give a reason for your answer.

Explain why both curves level off at the same amount of hydrogen iodide.

Write the balanced equation for the reaction of ammonia solution with dilute sulfuric acid.

Describe how the student could obtain a sample of pure, dry ammonium sulfate crystals in the laboratory.

Both reactants are solutions.

Complete the table by stating, for the industrial production, where the ammonia (i) and the sulfuric acid (ii) come from.

Other than the mass of product made, give two other differences between the laboratory preparation and the industrial production of ammonium sulfate.

State one way in which the chemistry of the two preparations is the same.

Ammonia is manufactured by the Haber process.

$\mathrm{N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)}$

The forward reaction gives out heat energy and is exothermic.

A company operates its Haber process plant at a temperature of $450\,^{\circ}\mathrm{C}$, a pressure of $200$ atmospheres and with an iron catalyst.

Explain why these conditions are used, rather than conditions that would give the greatest possible equilibrium yield of ammonia.

Using the table, describe how the equilibrium yield of ammonia changes as the pressure is increased at a constant temperature of $350\,^{\circ}\mathrm{C}$.

Explain why a manufacturer does not operate the Haber process at $200\,^{\circ}\mathrm{C}$, even though the equilibrium yield of ammonia would be much higher.

Explain why the manufacturer chooses to work at $200$ atm rather than at $400$ atm.

The unreacted nitrogen and hydrogen leaving the reaction vessel are recycled. Give one economic advantage of doing this.