Ii)Select the Least Reactive Non-Metal (1Mk)

NAME:………..………………………………………………………… INDEX NO:…………..……

SCHOOL:……………………………………………………………………………………………….

The section below represents part of the periodic table study it and answer the question that follow. The letters are not the actual symbol of the elements.

Q
X / H / O / T
Y / A / V
Z / S

i)Which element will require the largest amount of energy to remove one of the outer most electrons? In group 1 (1mk)

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ii)Select the least reactive non-metal (1mk)

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iii)Which of the elements has the greatest tendency of forming covalentcompounds in nature?Explain your choice. (2mks)

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iv)What name is given to the family of elements to which element ‘A’ belong? (1mk)

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v)Explain why the atomic radius of T is smaller than that of O (2mks)

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vi)Ions of element m (M2+) have an electronic configuration of 2.8.8. Place element M on the above grid. (1mk)

vii)When 6 litres of bromine gas were completely reacted with element D, it forms D2+ and 46g of the product. Determine the relative atomic mass of element D. (Atomic mass of bromine =80; molar gas volume =24 liters) (3mks)

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The flow chart given shows an analysis of mixture K that contains two salts.Study it and answer the question that follows.

(a)Name substances L,M and N (1½mks)

L…..……………………………………………………………………………………

M………………………………………………………………………………………

N ………………………………………………………………………………………

(b)What condition is necessary for step 1 to take place? (1mk)

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(c)State the colour changes that the metal oxide undergoes when hot and cold (1mk)

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(d)Write down an equation to show how

(i) Solution N is formed (1mk)

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(ii) Colourless solution A and NH3(aq) are formed. (1mk)

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(e)When excess NaOH(aq)is added to a solution Na white precipitate is formed which subsequently dissolves. Give the name and formula of the complex ion formed (1mk)

Name:…………………………………………………………………………………………………………………………

Formula:………………………………………………………………………………………………………………………

Explain why it was necessary to dissolve mixture K in water and then to filter (1mk)

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(f)7 grams of sodium carbonate and sodium chloride were dissolved in water. The solution was found to neutralize 25cm3 of a solution of nitric acid containing 63gdm-3, determine the percentage of sodium carbonate in the mixture.

(Na = 23, C =12, O = 16, H = 1, N= 14) (3mks)

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(g)(i) State the observation made if two samples of anhydrous sodium carbonate are added to a solution of hydrogen chloride in water and a solution of hydrogen chloride in water and a solution of hydrogen chloride in methylbenzene respectively. (1mk)

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(ii) Explain your observation in (g) (i).(1mk)

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Study the given diagram and answer the questions that follow.

(a)Name A,B and C (1½mks)

A………………………………………………………………………………………………

B………………………………………………………………………………………………

C .……………………………………………………………………………………………

(b)(i) Give two elements that are the most appropriate to be used as electrodes (1mk)

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(ii) Explain your answer in b (i) (1mk)

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(c)(i) State the observation made on the bulb after the electric current was switched on (1mk)

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(ii) Explain your answer in C (i) (1mk)

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(d)(i) Arrange the following anions in the order of increasing ease of discharge during electrolysis: (1mk)

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(ii) Dilute magnesium sulphate solution was electrolysed using copper electrodes. Write an Ionic equation to show the reaction occurring at the: (2mks)

Anode:…………………………………………………………………………………………………………………

Cathode:………………………………………………………………………………………………………………

(e)An electric current of 2.5 amperes was passed through molten lead (II) bromide for 40 minutes. Calculate the volume of bromine vapour that would be produces.(faraday’s constant =96,500 coulombs, molar volume = 24.0 dm3) (3mks)

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(a) Study the information in the table below and answer the questions that follow

Number of carbon atoms per molecule / Relative molecular mass of hydrocarbons
2 / 28
3 / 42
4 / 56

(i) Write general formula of the hydrocarbons in the table (1mk)

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(ii) Predict the relative molecular mass of the hydrocarbon with 5 carbon atoms. (1mk)

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(iii) Determine the molecular formula of the hydrocarbons in (ii) above and draw its structural formula (H =1.0, C = 12.0) (2mks)

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(b)The scheme below shows some reactions starting with propanol study it and answer the questions that follow.

Write down the formula of compounds S and T. (2mks)

S………………………………………………………………………………………………………………………………………

T………………………………………………………………………………………………………………………………………

(i)Draw the structural formula of compound B (1mk)

(ii)Namethe type of reaction, reagent and conditions for the reactions in step 1 and step IV. (3mks)

Reaction…………………………………………………………………………………………………………………………

Reagent……………………………………………………………………………………………………………………………

Conditions………………………………………………………………………………………………………………………

Step / Type of reaction / Reagents / Condition
I
IV

(iii)State two chemicals tests that can be used to differentiate propanol from propanoic acid (2mks)

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The diagram below shows the extraction of aluminium mental

(a)(i) The1ststep in the extraction of aluminium is the purification of bauxite name one impurity in the bauxite. (1mk)

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(ii) Why are the positive electrodes replaced at regular intervals? (2mks)

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(iii)Write the ionic equation for the reaction that takes place at the cathode (1mk)

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(iv)Electrolysis of alumina is carried out at 800c although the melting point of

alumina is 20270c. Explain (2mks)

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(v) What property of aluminium makes it suitable for making aluminium foil? (1mk)

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(vi) A scientist discovered an ore and suspected an ore and suspected zinc to be

presented. Describehow you would confirm the presence of Zinc. (3mks)

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(b) (i)What is anodizing? (½mk)

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(ii) State the importance of anodizing ( ½ mk)

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The diagram given shows the laboratory preparation of nitrogen

(a) (i)NameK and L (1mk)

K…………………………………………………………………………………………

L…………………………………………………………………………………………

(ii)Explain how apparatus Lfunctions (1mk)

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(iii) What is the role of copper in this experiment (1mk)

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(iv) Write down an equation to show how solution K plays its role (1mk)

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(v) Give one use of nitrogen in human reproduction (1mk)

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(b) Study the diagram given and answer the following question

(b) (i) State one observation made in the boiling tube containing lead (II)nitrate (1mk)

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(ii) Write an equation to show the reaction that produces the observation in b(i)(1mk)

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( c) (i) Name liquid C and Gas D

C…………………………………………………………………………………………………………………

D…………………………………………………………………………………………………………………

(ii) Explainhow liquidC is formed.

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(iii) How canthe identity of gas D be confirmed?

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The table below shows the results obtained when Potassium carbonate was reacted with excess of 1.0m Sulphuric acid at room temperature.

Time (seconds) / 5 / 10 / 15 / 20 / 30 / 40 / 50 / 60 / 70 / 80
Total Volume of gas (cm3) / 20 / 35 / 50 / 61.5 / 82.5 / 95 / 100 / 103 / 104 / 104

i)Plot a graph of volume (Y-axis) against time taken.

ii)Write down an equation showing the reaction that took place. (1mk)

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iii)Find out the total volume of gas produced at the end of the 35th second. (½mk)

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iv)Determine the total volume of gas produced by the end of the reaction.(½mk)

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v)Calculate the mass of Potassium Carbonate used in this reaction.

( K=39, C=2, O=16, molar gas volume=24.0 litres. )(3mks)

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vi)Calculate the average rate of production of the gas in the interval 25 by 40 seconds. (2mks)

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vii)If the same experiment was repeated using excess 2.5m sulphuric acid in place of the 1.0m Sulphuric acid, what would be the effect of-

The total gas of the volume produced at the end of the experiment? Explain

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II. The total time taken for the completion of the reaction. Give a reason.(2mks)

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