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Study the information in the table below and answer the questions that follow. The letters do not represent the symbols of the elements.
a) Write the electrons arrangement for the atom formed by elements and M and Q
b) Select an element which is
d) Element R lodes its outermost electron more readily than I. Explain e) Using dots(.) and crosses (x) to represent outermost electrons show bonding in the compound formed elements N and Q. f) Explain why the melting point elements M is higher than that of element . g) Describe how a solid mixture of sulphate of R and lead sulphate can be separated into solid samples.
Expected Response
a) The flow chart below shows a sequence of reactions starting with.
Study and answer the questions that follow. 
Cu = 63.5, Fe = 56.0
Expected Response
a) The diagram below shows a set –up used by as a student in an attempt to prepare and collect oxygen gas
c) The reaction between sulphur dioxide and oxygen to form trioxide in the contact process in exothermic. 
Factory manufacturing sulphuric acid by contact process produces 350kg of sulphur trioxide per day (conditions) for the reaction catalyst. 2 atmospheres pressure and temperatures between. (400 – 5000C) i) What is meant by an exothermic reaction? ii) How would the yield per day of sulphur trioxide be affected Temperatures lower than 40000C are used? Explain.
Expected Response
a) When an organic compound Y is reacted with aqueous sodium carbonate, it produces carbon dioxide reacts with propanol to form a sweet smelling compound Z whose formula is.
c) The scheme below was used to prepare a cleaning agent. Study and answer the questions that follow. 
i) What name is given to the type of cleaning agent prepared by the method shown in the scheme?
ii) Name one chemical substance added in step II iii) What is the purpose of adding the elements substance names in C(ii) above. iv) Explain how an aqueous solution of the cleansing removes oil from utensils during washing.
Expected Response
10cm3 of concentrated sulphuric (VI) acid was diluted to 100cm3. 10cm3 of the Resulting solution was neutralised by 36cm3 of 0.1M sodium hydroxide solution. Determine the mass of sulphuric (VI) acid that was in the concentrated acid (S = 32.0; H = 1.0; O = 16.0).
ANSWERS
Ammonium ion has the following structure:
Label on the structure: 
(a) covalent bond;
(b) coordinate (dative) bond.
ANSWERS
Study the information in the table below and answer the questions that follow: A mixture containing 35g of CuS04 and 78g of Pb(N03)2 in l00g of water at 60°C was cooled to 40°C.
(a) Which salt crystallised out? Give a reason
(b) Calculate the mass of the salt that crystallised out.
ANSWERS
A sample of water in a beaker was found to boil at 101.5°C at 1 atmospheric pressure.
Assuming that the thermometer was not faulty, explain this observation.
ANSWERS
The table below shows properties of some elements A, B, C and D which belong to the same period of the periodic table. The letters are not the actual symbols of the elements.
(a) Arrange the elements in the order they would appear in the period. Give a reason.
(b) Select the metallic element which is the better conductor of electricity. Give a reason.
ANSWERS
(a) BDACAcross the period the atomic radius decreases.
(b) D Across the period the conductivity increase due to increase in delocalised electrons.
In an experiment, dry hydrogen gas was passed over heated Lead (II) Oxide as shown in the diagram below.
State and explain the observations made in the combustion tube.
ANSWERS
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
Charcoal is a fuel that is commonly used for cooking. When it burns it forms two oxides.
(a) Name the two oxides. (b) State one use of any of the two oxides.
ANSWERS
(a) Carbon (IV) Oxide and Carbon (II) Oxide
(b) CO2- Fire extinguishers Fizzy drinks Food preservative . Solvay process . CO -Manufacture of fuel (water gas) Reduction in the extraction of metals Manufacture of methanol
The set – up below was used during the electrolysis of aqueous magnesium sulphate using inert electrodes
i) Name a suitable pair of electrodes for this experiment ii) Identify the ions and cations in the solution iii) On the diagram label the cathode iv) Write ionic equations for the reactions that took place at the anode. v) Explain the change that occurred to the concentration of magnesium sulphate solution during the experience. vi) During the electolysis a current of 2 amperes was passed through the solution for 4 hours. Calculate the volume of the gas produced at the anode.(1 faraday 96500 coulombs and volume of a gas at room temperature is 24000cm3) vii) One of the uses of electrolysis is electroplating What is meant by electroplating? Give tow reasons why electroplating is necessary.
Expected Response
The table below gives the volume of the gas provided when different volumes of 2M hydrochloric were reacted with 0.6g of magnesium powder at room temperature
(a) Write an equation fro the reaction between magnesium and hydrochloric acid
(b) On the grid provided plot a graph of the volume of gas produced (vertical axis), against the volume of acid added (Note the reaction comes to completion, the volume of the gas produced directly proportional to completion, the acid added). From the graph determine c)
e) Given that one mole of the gas occupied 24000cm3 at room temperature.
Expected Response
The table below shows the PH values of solutions I, II, III and IV. 
(a) Which solution is likely to be that of calcium hydroxide?
(b) Select the solution in which a sample of aluminium oxide is likely to dissolve. Give reason for your answer
Expected Response
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December 2024
AuthorMaurice Atika is a teacher and a netprenuer. |
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