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​These are chemistry questions and answers categorized according to topics, papers i.e. Paper 1 and 2, Levels i.e. form 1 to form 4, kcse year the examination was done and section A or B
Select topic/category to open topical questions from that particular option provided. ​Chemistry Topics
a) The solubility of the salt (2mks)b) The percentage of the salt in the saturated solution (1mk)
You are provided with solid potassium hydrogen carbonate. Describe how a solid sample of potassium nitrate can be prepared.
ANSWERS
Measure a certain volume of dilute nitric(V) acid and place it in a beaker;
Add potassium hydrogen carbonate little by little as the mixture is stirred until effervescence stops; Evaporate the solution to saturation and allow to cool for crystals to form; Dry the crystals in between filter papers.
Describe an experiment to show that group one elements react with cold water to form alkaline Solutions
ANSWERS
(a) Define a soluble base.
(b) Aqueous solutions of 2M ethanoic acid and 2M nitric(V) acid were tested for electrical conductivity. Which solution is a better conductor of electricity? Explain.
ANSWERS
(a)A soluble base is a substance that dissociates in water to produce hydroxide ions as the only negative ions.
(b)Nitric(V) acid. This is because nitric(V) acid is a strong acid and dissociates completely in solution producing many H+ ions.
Starting with copper, describe how a pure sample of copper(II) carbonate can be prepared.
ANSWERS
A sample of water is suspected to contain sulphate ions. Describe an experiment that can be carried out to determine the presence of sulphate ions.
ANSWERS
A mixture contains ammonium chloride, copper (II) oxide and sodium chloride. Describe how each of the substances can be obtained form the mixture.
ANSWERS
A compound whose general formula is M(OH)3 reacts as shown by the equation below.
(a) What name is given to compounds which behave like M(OH) 3 in the two reactions.
(b) Name two elements whose hydroxides behave like that of M.
ANSWERS
(a) Amphoteric
(b)Lead, Zinc and Aluminium
Iron (III) oxide was found to be contaminated with copper (II) sulphate. Describe how a pure sample of iron (III) oxide can be obtained.
ANSWERS
Starting with sodium metal, describe how a sample of crystals of sodium hydrogen carbonate may be prepared.
ANSWERS
React sodium with water to get sodium hydroxide. Bubble into this solution excess carbon (IV) oxide to get sodium hydrogen carbonate
Starting with copper turnings. describe how a sample of copper(II) sulphate crystals can be prepared in the laboratory. (3 marks)
Expected Response
Starting with barium nitrate solution, describe how a pure sample of barium carbonate can be prepared in the laboratory.
ANSWERS
Describe how samples of lead (II) sulphate, ammonium chloride and sodium chloride can be obtained from a mixture of the three.
ANSWERS
(a) The scheme below shows some of the reaction of solution D. Study it and answer the questions that follow
(i) Give a possible caution present in solution D
(ii) Write an ionic equation for the reaction in Step II (iii) What observations would be made in Step V? Give a reason (iv) Explain why the total volume of hydrogen gas produced in step 1 was found to be very low although calcium and solution D were in excess. (v) State one use of substance E. (b)Starting with solid sodium chloride, describe how a pure sample of lead (II) Chloride can be prepared in the laboratory (c) (i) State a property of anhydrous calcium chloride which makes it suitable for use as a drying agent for chlorine gas. (ii) Name another substance that can be used to dry chlorine gas
ANSWERS
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January 2025
AuthorMaurice Atika is a teacher and a netprenuer. |
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