The mass number of a carbon atom that contains six protons, eight neutrons, and six electrons is

Match the items in LIST A with the responses in LIST B by writing the letter of the correct response beside the item number. LIST A (i) Its hydroxide is used in soil treatment. (ii) It is obtained from its ore in the blast furnace. (iii) It gives a lilac colour when placed in a non-luminous flame. (iv) It forms an insoluble sulphate. (v) It is in the same group in the periodic table with nitrogen. (vi) It reacts with hydrogen to form a compound which is a liquid at room temperature. (vii) It is used in filament lamps. (viii) It is the strongest oxidizing agent among the halogens. (ix) It exists in three main forms. (x) Its chloride is added to food in order to give taste. LIST B A Barium B Lithium C Iron D Potassium E Oxygen F Fluorine G Sulphur H Argon I Phosphorus J Sodium K Magnesium L Carbon M Neon N Silicon O Calcium

1. Its hydroxide is used in soil treatment. (1 mk)
2. It is obtained from its ore in the blast furnace. (1 mk)
3. It gives a lilac colour when placed in a non-luminous flame. (1 mk)
4. It forms an insoluble sulphate. (1 mk)
5. It is in the same group in the periodic table with nitrogen. (1 mk)
6. It reacts with hydrogen to form a compound which is a liquid at room temperature. (1 mk)
7. It is used in filament lamps. (1 mk)
8. It is the strongest oxidizing agent among the halogens. (1 mk)
9. It exists in three main forms. (1 mk)
10. Its chloride is added to food in order to give taste. (1 mk)

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(a) (i) State two conditions required for iron to rust. (ii) List two methods which are used to prevent rusting of iron. (b) State three properties that make aluminium useful in overhead cables.

1. List two methods which are used to prevent rusting of iron. (2 mk)
2. State three properties that make aluminium useful in overhead cables. (3 mk)

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(a) Give three examples in each of the following: (i) Solid fuel (ii) Gaseous fuel. (b) The reaction which produces methanol from carbon monoxide and hydrogen is represented by the equation CO(g) + 2H₂(g) ⇌ CH₃OH(g) ΔH = -94kJmol⁻¹. The reaction is carried out at high pressure to give a good yield of methanol. (i) Explain why increase in pressure gives a better yield of methanol. (ii) The value of ΔH is negative. What does this tell about the reaction? (iii) With a reason, state whether a high temperature or low temperature will give a better yield of methanol.

1. Give three examples in each of the following: (i) Solid fuel (ii) Gaseous fuel. (2 mk)
2. With a reason, state whether a high temperature or low temperature will give a better yield of methanol. (3 mk)

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(a) (i) Explain, in terms of electronic configurations, why sodium and potassium elements have similar chemical properties. (ii) State the trend in reactivity of group I elements in the Periodic Table and give reasons for it. (b) Use the knowledge of periodic Table to complete Table 1. Table 1 S/n Name of element Atomic number Electronic configuration (i) Lithium (ii) 13 (iii) 2.8.7

1. State the trend in reactivity of group I elements in the Periodic Table and give reasons for it. (4 mk)
2. Use the knowledge of periodic Table to complete Table 1. (5 mk)

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Which crop grows best in the: (i) Most acidic soil? (ii) Least acidic soil? (iii) Neutral soil? (b) Suggest one best method for separating each of the following mixtures: (i) Common salt and water (ii) Iodine and sand. (iii) Pieces of iron and sand.

1. Use the information in Table 2 to answer the following questions: (i) Which crop grows best in acidic soil? (ii) Which crop requires a neutral soil? (iii) Which crop prefers a slightly alkaline soil? (iv) State the range of pH values suitable for growing cabbage and cauliflower. (4 mk)
2. Which crop grows best in the neutral soil? (1 mk)
3. Suggest one best method for separating pieces of iron and sand. (1 mk)

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Briefly explain what will happen when (i) concentrated sulphuric acid is exposed to the atmosphere? (ii) iron (II) sulphate is exposed to air for a long time? (iii) a bottle containing AgNO is left open? 3 (b) Give three applications of the process of neutralization in daily life.

1. Briefly explain what will happen when a bottle containing AgNO is left open? (2 mk)
2. Give three applications of the process of neutralization in daily life. (3 mk)

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Give the names or formula of the two chemicals that would be used in the laboratory to make each of the following gases. State a simple test that could be used to identify each gas. (i) Oxygen. (ii) Hydrogen. (iii) Carbon dioxide. (b) Suggest a suitable indicator for the following titrations: (i) Hydrochloric acid against ammonia solution. (ii) Sulphuric acid against sodium hydroxide solution. (iii) Ethanoic acid against potassium hydroxide solution.

1. Give the names or formula of the two chemicals that would be used in the laboratory to make carbon dioxide. State a simple test that could be used to identify carbon dioxide. (2 mk)
2. Suggest a suitable indicator for the titration of ethanoic acid against potassium hydroxide solution. (1 mk)

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(a) (i) What type of a chemical bond is found between fluorine atoms in a fluorine molecule? (ii) Name other type(s) of chemical bond formed by fluorine with other elements. Give an example of a compound in which fluorine form this type of bond. (b) Compound X contains 24.24% carbon, 4.04% hydrogen and 71.72% chlorine. Given that, the vapour density of X is 49.5. (i) Calculate the molecular formula of the compound X. (ii) Draw and name the displayed/open structure formula of the possible isomer(s) from the molecular formula determined.

1. Name other type(s) of chemical bond formed by fluorine with other elements. Give an example of a compound in which fluorine form this type of bond. (2 mk)
2. Draw and name the displayed/open structure formula of the possible isomer(s) from the molecular formula determined. (3 mk)

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(b) Name the following compounds according to the IUPAC system. (i) C$_5$H$_{12}$ (ii) CH$_3$ | CH$_3$CH$_2$-C-CH$_2$OH | CH$_3$ (iii) CH$_3$ | CH$_3$-C-CH$_2$OOH | CH$_3$

1. Fill in the missing information for Proton. (1 mk)
2. Calculate the molar mass of metal X. (4 mk)
3. Name C$_5$H$_{12}$ according to the IUPAC system. (1 mk)
4. Name CH$_3$ | CH$_3$CH$_2$-C-CH$_2$OH | CH$_3$ according to the IUPAC system. (1 mk)
5. Fill in the missing information for Electron. (1 mk)
6. Name CH$_3$ | CH$_3$-C-CH$_2$OOH | CH$_3$ according to the IUPAC system. (1 mk)
7. Fill in the missing information for Neutron. (1 mk)

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Describe the extraction of iron from the haematite ore and write all the chemical equations for the reactions involved in each stage of extraction.

1. Describe the extraction of iron from the haematite ore and write all the chemical equations for the reactions involved in each stage of extraction. (8 mk)

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Addition of inorganic fertilizers in the farm is not as important as addition of organic manure. Discuss the correctness of this statement in four points.

1. Discuss the correctness of the statement 'Addition of inorganic fertilizers in the farm is not as important as addition of organic manure' in four points. (4 mk)

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