Study the nuclear reactions given in the scheme below and answer the questions that follow.

(a). A and D are isotopes. What is meant by the term isotope?

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(b). Write an equation for the nuclear reaction in step I.

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(c). Give one use of radioactive carbon-14.

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The electron arrangement of elements A, B, C, and D are A = 2.8.8, B = 2.8.6, C = 2.8.2, D = 2.8.1

(a). Select the element which forms.

i. A divalent anion.

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ii. A soluble carbonate.

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(b). Which element has the largest atomic radius?

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(a). Give a reason why alkali metals are stored under oil.

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(b). Write the equation for the reaction between sodium and cold water. ..............................................................................................................................................................

Charcoal burns to form Carbon (IV) oxide and produces of heat energy.

(a). Write the thermo chemical equation for the combustion of charcoal. ..............................................................................................................................................................

(b). In the space provided, sketch a simple energy level diagram for the above reaction.

5 g of Sodium Carbonate were dissolved in 20cm3 of water in a boiling tube. Lemon juice was then added drop wise with shaking until there was no further observable change.

(a).State and explain the observation which was made in the boiling tube when the reaction was in progress.

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(b).Explain what would happen if the lemon juice was added to copper turnings in a boiling tube? .................................................................................................................................................................

A student labelled solutions of Sodium Chloride, Lead nitrate, Zinc sulphate and distilled water as A, B, C and D. Respectively, but realised that there was a mistake in labelling. She carried out tests to identify the solutions.

(a).When aqueous Potassium iodide was added to each sample separately, a yellow precipitate was formed in solution A only. Identify solution A.

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(b).When excess ammonium Hydroxide was added to each sample separately, a white precipitate was formed in solution A and D only but the precipitate dissolved in solution D. Identify solution D. ............................................................................................................................................................

(c).When Silver nitrate was added to each sample separately a white precipitate was formed in solution B only. Identify solution C.

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(a).Distinguish between weak and strong acid. .................................................................................................................................................................

(b). Compare the reactivity of a weak acid and strong acid with magnesium ribbon.

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Describe a simple laboratory experiment that can be used to distinguish between sodium sulphite and sodium carbonate. .................................................................................................................................................................

The apparatus shown below was used to investigate the effect of Carbon (II) Oxide on Copper (II) oxide.

(a). State the observation made in the lime water. .................................................................................................................................................................

(b). Write the equation for the reaction that took place in the combustion tube. .................................................................................................................................................................

(c). Why was it necessary to burn the gas as shown.

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A current of 0.5 amperes was passed through molten chloride of element Q for 32 minutes and 10 seconds. 0.44g of Q was deposited at the cathode. If the R.A.M of Q is 88, determine the charge on ion of Q.

(1 F =96500 coulombs).

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The melting point of magnesium chloride is while that of phosphorous (III) chloride is -91c. The two elements are in the same period of the periodic table. In terms of structure and bonding explain the differences in their melting points. ................................................................................................................................................................. .................................................................................................................................................................

Hydrogen can form compounds in which its oxidation state is either -1 or +1. Explain. .................................................................................................................................................................

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Equal volumes of a mixture of Ethane and Chlorine reacted when exposed to U.V light.

(a). Name the type of reaction which occurred.

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(b). Give the structural formula and the name of the organic compound formed when Ethane and Chlorine react. ..............................................................................................................................................................

Hydrogen sulphide gas was bubbled through a solution of Lead (II) nitrate. Using an ionic equations explain the observation made during the reaction. ..............................................................................................................................................................

The chromatogram below shows the constituents of a flower extract M. Study it and answer the questions that follow.

(a). Which is the least soluble dye . Explain.

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(b). What does the line labelled A represent?

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(c). State one application of chromatography.

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The information given below relates to elements in the same group in the periodic table. Study it and answer the questions that follow.

(a). Which element has the shortest atomic radius. Give a reason. ..............................................................................................................................................................

(b). Which element would be a better conductor of heat and electricity. Give a reason. ..........................................................................................................................................................................

Describe how a solid sample of Lead (II) chloride can be prepared using the following reagents

-Dilute Nitric acid

-Dilute Hydrochloric acid

-Lead (II) carbonate.

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(a). State Gay –Lusac’s Law.

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(b). What volume of Methane would remain unreacted if a burner containing 40cm3 of the gas burns in 40cm3 of enclosed air. (Assume that Oxygen forms 20% by volume of air.) The equation for the reaction is as shown below.

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When a Hydrocarbon was completely burnt in Oxygen, 4.2 g of Carbon (IV) oxide and 1.71g of water were formed. Determine the empirical formula of the Hydrocarbon. ( C = 12, 4 = 1, O = 16.

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Ammonium nitrate was heated as shown below.

(a). Identify gas B

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(b). State and explain one precaution that must be taken before heating is stopped. ..............................................................................................................................................................

The diagram below represents the extraction of sulphur by the Frasch process.

a) What is the purpose of the hot compressed air in this process.

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b) State the conditions of the contents of tube II.

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a) What is a green house gas?

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b) Explain why chlorine is termed as one of the green house gases.

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The curves below were obtained when equal volumes of hydrogen peroxide of the same concentration were allowed to decompose separately. In one case manganese (IV) oxide was added to hydrogen peroxide.

a) Write an equation for the decomposition of hydrogen peroxide.

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b) Which curve represents the decomposition of hydrogen peroxide with manganese (IV) oxide? Explain. ..................................................................................................................................

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ii) Calculate the value of the cell in b(i)

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0.12g of a divalent metal N dissolves in 50cm3 of 0.5M sulphuric acid. The resulting solution required 5.0cm3 of 1.0M sodium hydroxide solution to neutralise the excess acid.

i) Calculate the number of moles of sulphuric acid that reacted with sodium hydroxide. ............................................................................................................................................................

ii) Determine the number of moles of the acid that reacted with the divalent metal N. ..................................................................................................................................

iii) Determine the relative atomic mass of metal N.

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When bromine gas reacts with aqueous sodium hydroxide, the equilibrium represented by the equation below is established.

What observation would be made if a few drops sulphuric (vi) acid were added to the equilibrium mixture. ..................................................................................................................................

a) Name the major ores of Iron Metal.

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b) Iron from the blast furnace is alloyed with elements such as carbon, manganese and chromium. State two importances of adding these elements. ..................................................................................................................................

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