Q.1 (a)
Chlorine is the subject of the following questions :
(i) What is the atomicity ?
(ii) Name
the compounds formed when chlorine react with water.
(iii)
Chlorine reacts with white phosphorus forming phosphorus trichloride
and phosphorus pentachloride . Write balanced equation for the
formation of each of these compounds.
Q.1(b) Answer the following questions,
relating your answer only to salts in the list given
below:
Anhydrous calcium chloride, copper sulphate-5-water,
sodium carbonate-10-water.
(i) Which compound is efflorescent
?
(ii) Which compound is blue in colour ?
(iii) Which compound
is deliquescent ?
(iv) What would be seen in mixing a
solution of calcium chloride with a solution of sodium carbonate
?
(v) Write a balanced equation for the reaction occurring when a
solution of calcium chloride is mixed with a solution of sodium
carbonate.
Q.1(c) In this question you are required
to supply the word (or words) that will make each sentence in
to a correct statement which to be written down in
full.
Example: sodium reacts with chlorine to form
sodium chloride.
Answer: Molten
sodium reacts with chloride to form sodium chloride.
(i) The
electrolysis of lead bromide liberates lead and bromine.
(ii)
Copper sulphate crystals are dehydrated by sulphuric acid.
(iii)
Calcium nitrate reacts with sodium sulphate to form calcium
sulphate. (same word is required in two places.)
(iv) Crystals of
sulphur are obtained when a solution of sulphur in carbon disulphide
is allowed to evaporate.
Q.1(d) If a crop of wheat removes 20 kg of
nitrogen per hectare of soil, what mass of the fertilizer calcium
nitrate Ca(NO3)2 would be required to replace
the nitrogen in a 10-hectare field ? (N = 14; O = 16; Ca = 40.
Answer to the nearest kg.)
Q.1(e)(i) A vessel contains N molecules
of oxygen at a certain temperature and pressure. How many molecules
of sulphur dioxide can the vessel accommodate at the same
temperature and pressure ?
(ii) Each of two flasks contains 2.0 g
of gas at the same temperature and pressure. One flask contain
oxygen and the other hydrogen.
1. Which sample contains the
greater number of molecules ?
2. If the hydrogen sample contains N
molecules, how many molecules are present in the oxygen sample ? (H
= 1; O = 16.)
(iii) A gas sample occupies 4 litres at
270C and P atmospheric pressure. What would be its volume
at 3270C and 2P atmospheric pressure ?
Q.1(f) Describe, in each case,
one chemical test that would enable you to distinguish
between the following pairs of chemicals. Describe what happens with
each chemical or state no 'visible reaction'.
(i) sodium chloride
solution and sodium nitrate solution ;
(ii) sodium sulphate
solution and sodium chloride solution ;
(iii) calcium nitrate
solution and zinc nitrate solution;
Q.1(g) Write balanced equations for each of
the following reactions :
(i) Magnesium heated in nitrogen
;
(ii) Action of heat on sodium nitrate ;
(iii) Action of heat
on copper nitrate ;
(iv) Zinc and dilute sulphuric acid ;
(v)
Ethene and hydrogen ;
(vi) Nitrogen monoxide and
oxygen.
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