1. MANUFACTURED SUBSTANCES IN INDUSTRY

3. A) Sulphur dioxide is produced from one of these reaction : i) Sulphur is burnt in air to produce sulphur dioxide : S + O₂ SO₂ ii ) Lead (II) sulphide is roasted, also to produce sulphur dioxide. 2PbS + 3O₂ 2SO₂ + 2PbO

4. b) Impurities such as water vapour and arsenic compound are removed to prevent poisoning of the catalyst

5. a) Sulphur dioxide is then mixed with excess oxygen. b) Sulphur dioxide is oxidised to sulpur trioxide : 2 SO2 + O2 2 SO2 STAGE II – FORMATION OF SULPHUR TRIOXIDE

6. Conditions for optimum products : i ) The presence of vanadium (v) oxide as catalyst ii) Temperature between 450 0C – 550 0C iii) pressure of 1 atm

7. A) Sulphur trioxide is dissolved in concentrated sulphuric acid to form oleum : SO 3 + H 2 SO 4 H 2 S 2 O 7 ( Oleum) B) The oleum produced is then diluted with water to produced concentrated sulphuric acid : H 2 SO 4 + H 2 O 2H 2 SO 4 STAGE III – FORMATION OF SULPHURIC ACID

8.  However, this is not done in industry to produce sulphuric acid… Explain  - Because SO 2 has low solubility in water.  - SO 2 react violently in water producing large amount of heat

9. 3 USES OF SULPHURIC ACID: To manufacture fertilizersTo manufacture detergents Use as electrolytes in car

10. Factory, vehicles, burning of plastics SO2 gas in air come from Cause coughing, chest paint, shortness of breath, lung disease and bronchitis Effect of inhaling gas SO2 Acidic substance that dissolve in rain water ACID RAIN

11.  Sulphur dioxide is released through burning of petrol in cars and also released through chimney of factories.  Wind carries the pollutants around the globe.

12.  Sulphur dioxide causes respiratory problems in human.  The gas reacts with water to form acid rain. This acid rain corrodes buidings and metal structures

13. WATER POLLUTION  Acid rains destroy trees in forests.  Acid rains flows into lakes and rivers and caused fish and other aquatics organisms die.

14. SOIL POLLUTION PH of the soil decrease. Roots the soil are destroyed. Plants die of malnutrition and diseases.

15.  i) Use non-leaded petrol or low – sulphur petrol.  Use catalytic converters in motor vehicles to clean up emissions from car engines.  Use alternative sources of energy to replace fossil fuels; i.e steam, solar, wind, waves, biomass.

16. USES OF AMMONIA  i) To manufacture nitrogenous fertilizers such as ammonium nitrate and urea.  ii) To be converted into nitric acid and used for making explosive.  iii) To produce ammonium chloride ; used as an electrolyte in dry cells.

17. PROPERTIES FOR AMMONIA VERY SOLUBLE IN WATER PUNGENT SMELL COLOURLESS GAS LESS DENSE THAN AIR BURNS IN OXYGEN BUT NOT IN AIR ALKALINE GIVES A WHITE FUMES WHEN REACT WITH WATER

19. Ratio of hydrogen &nitrogen gas ?  1 mole N 2 : 3 moles H 2

20.  3 conditions for manufacture ammonia : Optimum temperature (450°C – 550°C) Optimum pressure ( 200-500 atm) Using iron as catalyst

21. Equation to form ammonia : N 2 + 3H 2 2NH 3

22. ALLOYS

23.  i) Lusters means metals reflect light or have a shiny appearance.  ii) Ductility means metal can be pulled into wires.  Iii) Malleability is the property that allows metals to be hammered or rolled into thin sheets.

24.  iv ) Conductivity means that heat or electrical charges move easily through the material. Metals and alloys have high conductivity because some of their electrons are not tightly held by by their atoms.

25. E) Alloy – a mixture of a metal with one or more other elements where the mixture retains the properties of the metal. F) Alloys are produced to obtain a material with improved properties such as greater hardness, strength, lightness or durability

26. + Pure metal A Pure metal B ALLOY

27. Because …. - atoms are not of the same size.Not orderly arrangement.Less empty spaces between atoms. Therefore, when force is applied, layers of atoms do not slip or slide.

28. force Layers of atoms slide Atoms are ductile Atoms are malleable The shape of metal changes force

29. Atoms in pure metals are of the same size The atoms are also in orderly arragement There are less empty spaces in between the atoms. Therefore,when force applied, layer of atoms slide or slip easily

30.  H)Why is cutlery made of stainless steel and not iron?  They do not corrode easily  I) Why is pure iron not used to make building materials ?  Pure iron rust and corrode easily.

31. ALLOYS COMPOSITION OF ALLOYS & THEIR PROPERTIES BRASS STAINLESS STEEL BRONZE PEWTER STEEL DURALAMIN Made up mostly copper and tin.Hard and strong, does not corrode easily and has shiny surfaces Made up of copper and zinc, harder than copper Made up of 93% Aluminium. Light and strong COMPOSITION

32. ALLOYS COMPOSITION OF ALLOYS & THEIR PROPERTIES BRASS STAINLESS STEEL BRONZE PEWTER STEEL DURALAMIN Contains chromium ironand carbon. Shiny, strong and does not rust Made up 96% tin copper and antimony. Lustre, shiny and strong Hard and strong COMPOSITION

33.  3 aims in making alloys :  A) To increase the hardness and strength of a metal.  B) To prevent corrosion of rusting.  C) To enhance the appearance of the metal surface.