GCE 'O' 2012 Science (Chemistry) Paper 5
You are provided with a solid sample of salt P and a solid sample of salt Q
each in a stoppered test-tube. You are also provided with separate samples of
the aqueous solutions of salts P, Q and R.
Each salt contains only two ions and, between
them, the three salts contain two different cations and two different anions.
Carry out the following experiments. Test any
gases evolved. Carefully record your observations in Table 2.1
Table 2.1
Test
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Observations
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(a)
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Remove the stopper
from the test-tube labelled solid salt
P. Heat this test-tube gently and then more strongly until no further changes are seen.
While you are heating
the test-tube strongly, place a glowing splint near the neck of the
test-tube.
You must ensure that the splint does not fall into the test-tube.
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Repeat the process
above, this time using the test-tube labelled solid salt Q.
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(b) to (d) Perform the tests
described, and record your observations, in Table 2.2 on page 9.
The volumes given in Table 2.2 are
approximate and should be estimated rather than measured.
Table 2.2
Test
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Observations with
solution P
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Observations with
solution Q
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Observations with
solution R
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(b)
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Place 1cm3
of solution P in a large test-tube.
Add 1cm3
of dilute sodium hydroxide.
Gently warm the
mixture and then boil it for one minute.
Test any gases evolved
with litmus paper.
Add a piece of
aluminium foil to the test-tube and warm this mixture.
Test any gases
evolved with litmus paper.
Repeat part (b) using solution Q and
solution R.
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(c)
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Place 1cm3
of solution P in a test-tube.
Add 1cm3
of dilute nitric acid, followed by 1cm3 of silver nitrate
solution.
To the mixture,
add 1cm3 of aqueous ammonia solution and shake.
Repeat part (c) using solution Q and
solution R.
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(d)
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Place 1cm3
of solution P in a test-tube.
Add 1cm3
of dilute hydrochloric acid, followed by 1cm3 of barium chloride
solution.
Repeat part (d) using solution Q and
solution R.
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(e) Conclusions
Consider the
results of the experiments in parts (a) to (d).
Give four
different conclusions you can draw about salts P, Q and R, and the ions
they contain, from the chemical reactions you have performed.
Give evidence to
support each of your conclusions.
Conclusion 1 ……………………………………………………………………………………………
Evidence 1 ………………………………………………………………………………………………
Conclusion 2 ……………………………………………………………………………………………
Evidence 2 ………………………………………………………………………………………………
Conclusion 3 ……………………………………………………………………………………………
Evidence 3 ………………………………………………………………………………………………
Conclusion 4 ……………………………………………………………………………………………
Evidence 4 ………………………………………………………………………………………………
