(a)(i) Explain briefly the term chemical industry.
(ii) State three factors that should be considered in siting a chemical industry.
(b)(i) Describe briefly twin is extracted from its ore.
(ii) Give two uses of tin.
(c)(i) Name the constituents of cement.
(ii) How does mortar set?
(d)(i) Explain briefly the term pollution.
(ii) Give two examples of air pollutants.
(e) Consider the following reversible reaction which occurred at the temperature of 298K:
N\(_{2(g)}\) + 3H\(_{2(g)}\) \(\rightleftharpoons\) 2NH\(_{3(g)}\); \(\bigtriangleup\)H = —92.37kJ
Explanation
(a)(i) Explain briefly the term chemical industry: It is an industry which uses chemical processes convert raw materials into useful products.
(ii) State 3 factors that should be considered in sitin chemical industry. (1) Availability of resources needed. (2) Good communication skills. (3) Nearn to markets. (4) Availability of labour. (5) Availability of space. (6) Good climate condition. (7) Favourable transport system (8) Nearness to source of energy. (9) Nearness to raw materials (10) Government policy.
(b)(i) Describe how tin is extracted from its ore: The ore is crushed into powder, washed with water and filtered to remove impurities/concentration of ore. The ore is roasted in air to remove impurities. roasted is mixed with coke/charcoal and heated in a furnace/high temperature/1300°C where it is reduced to tin/C + SnO\(_2\) ---> Sn + O\(_2\). Limestone is added to remove earthly impurities as slag/CaCO\(_2\) + SiO\(_3\) ---> CaSiO\(_3\) + CO\(_2\) Molten tin is tapped off.
(ii) It is used to coat iron or steel (as a protection aga corrosion). It is used in making alloys (e.g. Bronze, type metal, solder).
(c)(i) Name the constituents of cement: Calcium oxide/Calcium trioxocarbonate(IV), Silicon(IV) oxide and Aluminium oxide.
(ii) How does mortar set? Mortor is a mixture of sand, cements/lime and WE When mortar is placed between two blocks it absorbs CO\(_2\) from the atmosphere to form CaCO\(_3\) with m given out.
(d)(i).Explain briefly the term pollution: Pollution – introduction of harmful substance the environment/contamination of environment.
(ii) Give two examples of air pollutants: Gases hydrocarbon, e.g. methane (CH\(_4\)), CO, NO\(_2\), SO\(_2\), NO, CFC's, oxides of lead, particuate matter, e.g. d pollen grains, soot, smoke and smog.
(e)(i) Consider the following reversible reaction wh occurred at the temperature of 298k:
N\(_{2(g)}\) + 3H\(_{2(g)}\) \(\rightleftharpoons\) 2NH\(_{3(g)}\); \(\Delta\)H = –92.37KJ.
List two factors that would increase the yield of NH\(_{3(g)}\) — (1) Increase in pressure of the system/decrease in volume of system.
(2) Decrease in temperature of tho system.
(3) Removal of ammonia/products.