Page 152 - Chemistry

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-Place 50cm of solution D in 100ml glass beaker provided and record its steady temperature.
- Mark a cross (x) on a piece of white paper and place the beaker containing the thiosulphate on it.
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- Measure 5cm of solution E and add it to the beaker with the thiosulphate and swire
carefully not to pour the content.
- Start a stop watch immediately the last drop of acid is added
- Look through the solution and note the time taken for the mark to become invisible
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- Repeat the procedure with the thiosulphate heated to 30 C, 40 C, 50 C and 60 C

Record your results in table III below:
Table III
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Volume of thiosulphate Volume of solution Temperature ( C) Time 1 / t
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3
used (cm ) E used (cm ) (secs)
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25 5 Initial temp
25 5 30
25 5 40
25 5 50
25 5 60

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(a) Use your results to plot a graph of / t against temperature
(b) From your graph, determine the time taken if the temperature of the solution is 318K
(c) Explain how the rate of reaction changes with increase in temperature

QUESTION 3
Procedure 1:
You are provided with solid T.
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Place a spatula full of solid T in a clean boiling tube then add about 10cm of distilled water.
Shake the mixture for about 1 minute then filter. Divide the filtrate into 4 portions.
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(a) To the first portion add about 2cm of sodium hydroxide (solution A)
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(b) To the second portion add about 2cm of 2.0M hydrochloric acid
(c) To the third portion, add a few drops of phenolphthalein indicator
(d) To the fourth portion dip a clean glass rod and place the soaked end of the glass rod
onto a non-luminous flame

Procedure 2:
You are provided with solid X. Carry out the tests below and record your observation and
inferences in the table below:
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Place one spatula end full of solid X in a boiling tube and add about 10cm of distilled water.
Shake well and use for the tests below:
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(a) To the 2cm of solution in a test-tube, add one spatula end full of sodium hydrogen carbonate
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(b) To 2cm of solution, add three drops of acidified potassium manganate (VII) solution
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(c) Place about 5cm of ethanol in a test tube and add drops of concentrated sulphuric acid
then add a spatula end full of solid X. warm the mixture carefully. Shake well and pour
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the mixture into 20cm of water in a beaker

CONFIDENTIAL
Requirements:-
1. Solution X 1, acidified potassium manganate (VII) solution. It is prepared by dissolving
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3.16g of KMnO 4 in 400cm of 2M H 2SO 4. add distilled water to make it up to 1litre solution
2. Solution X 2, 0.1M Iron (II) Sulphate

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