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Chemistry - 1999( I.C.S.E)
You are on question 2 to 7
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SCIENCE
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Q2.(a) Choose
the Correct word or phrase from the bracket to complete the
following sentences :
(i) Ammonium chloride is a soluble salt
prepared by ___________ (precipitation, neutralization).
(ii) When ammonium chloride is heated,
it undergoes __________ (thermal decomposition, thermal
dissociation).
(iii) Heating
ammonium chloride with sodium hydroxide produces __________
(ammonia, nitrogen).
(iv) Heating
a solution of ammonium chloride and sodium nitrite produces
__________ (ammonia, nitrogen).
Q2.(b) Write the correctly
balanced equation for each of the reactions mentioned in statements
(i) - (iv) above.
Q2.(c) Describe what you see when
concentrated nitric acid is added to copper.
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Q.3(a)(i) What is
the colour of the flame seen when sulphur burns in air
?
Q.3(a)(ii) Name
the product formed when sulphur is burnt in air or oxygen.`
Q.3(a)(iii) When burning sulphur reacts with water, a
compound is formed. Name the compound.
Q.3(a)(iv) Write
the balanced equation for the reaction between sulphur dioxide and
moist chlorine.
Q.3(a)(v) In the reaction mentioned in
question (iv) above, which substance is the oxidizing
agent ?
Q.3(b)(i) What is the purpose of
the Contact Process ?
Q.3(b)(ii) Name the catalyst used in
the Contact Process.
Q.3(b)(iii) Write the balanced
equation for the reaction in the Contact Process which takes place
in the presence of the catalyst.
Q.3(c)(i) When hydrogen sulphide
reacts with oxidizing agents, what substance is always a product of
the reaction ?
Q.3(c)(ii) What is the colour of the
precipitation formed when hydrogen sulphide is bubbled through
copper sulphate solution ?
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Q.4(a) With
reference to the reduction of copper oxide, iron (II) oxide, lead
(II) and magnesium oxide by hydrogen, place the oxides in order of
increasing ease of reduction. That is, put first the oxide that is
most difficult to reduce ; and last, the oxide that is most easily
reduced.
Q.4(b) Write balanced equations
for the following reactions :
Q.4(b)(i) Reduction of
copper oxide by hydrogen.
Q.4(b)(ii) Reduction of iron
(III) oxide by carbon monoxide.
Q.4(b)(iii) Reduction of
lead (II) oxide by carbon.
Q.4(c)(i) What is the type of
bonding expected in a metallic chloride ?
Q.4(c)(ii) If a
fused metallic chloride is electrolysed, at which electrode would
the metal be obtained ?
Q.4(c)(iii) What metallic property
is shown by the non-metal graphite ?
Q.4(d)(i) Cast iron contains about
4% carbon. By what chemical process is the amount of carbon
decreased to make steel ?
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Q5.(a)
Concentrated nitric acid oxidises phosphorus to phosphoric acid
according to the following equation :
P + 5HNO3 ¾® H3PO4 + H2O +
5NO2
Q5.(a)(i)
What mass of phosphoric acid can be prepared from 6.2 g of
phosphorus ?
Q5.(a)(ii)
What mass of nitric acid will be consumed at the same time ?
Q5.(a)(iii) What would be the
volume of steam produced at the same time if measured at 760 mm Hg
pressure and 273oC ?
(H = 1; N = 14; O = 16; P = 31)
Q.5(b) Ammonia may be oxidized to
nitrogen monoxide in the presence of a catalyst according to the
following equation :
4NH3 + 5O2 ¾® 4NO +
6H2O
If 27 litres of reactants at the same temperature
and pressure ?
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Q.6(a) For each
of the compounds (i) Ethane, (ii) Vinegar and (iii) Marsh gas, draw
the relevant structural formula.
Q.6(b)(i) What word is used to describe these three
compounds taken together ?
Q.6(b)(ii) What is the special feature of the
structure of :
Q.6(b)(iii) What type
of reaction is common to both these compounds ?
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Q7(a) Define the following
terms :
(i) Acid
(ii) pH scale
(iii) neutralization
Q.7
(b)(i) Outline the steps that would be necessary to convert
insoluble lead (II) oxide into insoluble lead chloride.
Q.7
(b)(ii) Write the balanced equations for the reactions required
to convert insoluble lead (II) oxide into insoluble lead
chloride.
Q.7 (b)(iii) If iron reacts with dilute
sulphuric acid, what will be the products ?
Q.7 (b)(iv) A
solution of iron (III) chloride has a pH less than 7. Is the
solution acidic or alkaline ?
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