Useful Industrial Processes

7.1 Rates of Reaction

describe experiments to investigate the effect of temperature, concentration and particle size on the rate of a reaction

Investigate the effect of these factors using suitable reactions. Teachers may prefer to take each factor in turn and work through sections 333, 334, 335, 336 & 340 with it.

draw graphs and interpret the results of such kinetics experiments

Suitable reactions include: dilute hydrochloric acid and marble chips, magnesium and dilute hydrochloric acid, sodium thiosulphate solution and hydrochloric acid.

draw graphs and interpret the results of such kinetics experiments

predict the effect of changes in temperature, concentration and particle size and the presence of a catalyst on a given rate of reaction

state and explain that the rate of a chemical reaction increases if (i) the temperature is increased; (ii) the concentration of reactant is increased; (iii) the particle size of a solid reactant is decreased

understand that reactions can occur when particles collide and that increasing the frequency and/or energy of collisions increases the rate of the reaction

define a catalyst and describe its action

define enzymes as catalysts in biological systems and describe their use in the baking, brewing and dairy industries

Discuss that specific enzymes are required for specific reactions.

describe how the rates of enzyme-catalysed reactions vary with temperature

Link enzymes with living systems - body temperature - and denaturing at high temperatures.

7.2 Reversible Reactions

recall that some reactions are reversible

Illustrate that some reactions can go backwards as well as forwards.

recall that some reactions are reversible

recall that such reactions may reach a state of equilibrium

understand the principle of dynamic equilibrium

Discuss the idea that ‘forward’ and ‘backward’ reactions are taking place simultaneously leading to a dynamic equilibrium (analogy with running up a ‘down’ escalator). Use appropriate video material if available.

recall that, in industry, nitrogen and hydrogen are combined to form ammonia

Discuss the reaction used in the Haber process and state the raw materials and operating conditions. Use appropriate video material if available.

understand Le Chatelier’s Principle and be able to use it to predict effects of pressure and temperature changes on equilibrium

Discuss Le Chatelier’s Principle in general terms.

understand how the position of such an equilibrium is affected by changes of temperature and pressure by considering the Haber process as an example

Discuss the effects of changes in conditions on the yield of ammonia in the Haber process.

understand the consequential effects of these changes on the rate of attainment of equilibrium and the need to use a catalyst

Discuss the effects of changes in conditions on the rate of attainment of equilibrium in the Haber process and identify those which improve the yields as well.

understand the conditions used in the Haber process (see also ‘Reversible Reactions’)

Discuss the conditions used in terms of the yield and the rate of the reaction.

recall the manufacture of sulphuric acid from sulphur and sulphide ores

explain the manufacture of sulphuric acid from sulphur and sulphide ores

explain the operating conditions used in the Contact process

recall some uses of sulphuric acid to illustrate its economic importance

7.3 The Production and Effect of Fertilisers

recall that a nitrogenous fertiliser is manufactured by neutralising ammonia with nitric acid

Revise the process of neutralisation and reason for using it for making fertilisers.

recall that nitrogenous fertilisers promote plant growth

understand that the process of leaching of artificial fertilisers causes excessive plant growth in rivers and lakes and may be harmful to health

Discuss the sequence of events which may follow excessive use of artificial fertiliser. Use appropriate video material if available.