Page 175 - Chemistry

 Take six test-tubes of equal volume and label them 1to 4
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 Run 5cm of 1.0M Potassium iodide solution from a burette into each one of them.
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 Add 1.0cm of 1.0M Lead (II) nitrate solution to the test-tube labeled 1and stir the mixture
well with a glass rod.
 Add about 5 drops of ethanol to the mixture, stir and place it in test-tube rack.
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3
3
3
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 Add 1.5cm , 2.0cm , 2.5cm , 3.0cm and 3.5cm of the 1.0M lead (II) nitrate to the test-
tubes labeled 2, 3, 4, 5 and 6 respectively.
 Add about 5 drops of ethanol to each test-tube, stir and allow to settle
 Measure the height of the precipitate in each tube in (mm) and record the measurements in
the table below:

Test tube number 1 2 3 4 5 6
Volume of 1M lead (II) 1.0 1.5 2.0 2.5 3.0 3.5
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nitrate (cm )
Height of precipitate
(mm)
(a) Plot a graph of the heights of the precipitate against the volume of lead (II) nitrate
solution added
(b) Calculate the;
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(i) Number of moles of KI in 5cm of 1.0MKI solution
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(ii) Number of moles of Pb(NO 3) 2 solution which reacted completely with 5.0cm of 1.0M KI
(c) How many moles of KI would react with one mole of lead (II) nitrate?
(d) Write a balanced chemical equations or the reaction between lead (II) nitrate and
potassium iodide
(e) Give the ionic equation for the reactions
(f) What was the purpose of adding ethanol to the mixture?

Answers section I & II
1. Introduction to chemistry

1. a) F is place in the middle of the flame while G is placed at the upper region of the flame
b) Non- luminous flame

2. . A,D,C,B, and C all correct
A,D,C,D correct answers are exclusive
A,D,C ½ mk otherwise penalize
3. a) The laboratory gas burns in excess oxygen
OR burns completely or produces CO 2 and H 2O only
- No unburnt carbon remains
OR No soot is formed// Produced.
b)

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