CHEMISTRY WORKBOOK FOR CSEC
Anne Tindale
3 Contents List Section A A1 States of matter ..................................................................................................................4 A2 Mixtures and separations ................................................................................................8 A3 Atomic structure .............................................................................................................13 A4 Periodic table and periodicity .......................................................................................17 A5 Structure and bonding ...................................................................................................21 A6 Mole concept ...................................................................................................................27 A7 Acids, bases and salts .....................................................................................................35 A8 Oxidation–reduction reactions .....................................................................................49 A9 Electrochemistry .............................................................................................................54 A10 Rates of reaction ..............................................................................................................62 A11 Energetics .........................................................................................................................66 Section B B1 Sources of hydrocarbon compounds............................................................................70 B2 Organic chemistry – an introduction ..........................................................................73 B3 Reactions of carbon compounds ..................................................................................77 Section C C1 Characteristics of metals................................................................................................ 91 C2 Reactivity and extraction of metals ..............................................................................94 C3 Uses of metals ..................................................................................................................99 C4 Impact of metals on living systems and the environment ......................................101 C5 Non-metals ....................................................................................................................104 C6 Qualitative analysis ......................................................................................................115 Periodic table .........................................................................................................................121
A8 Oxidation–reduction reactions (cont.)
c) Using oxidation number to support your answer, state which reactant is acting as an oxidising agent and which is acting as a reducing agent in the following reaction.
CH4(g) + 4CuO(s) 4Cu(s) + CO2(g) + 2H2O(g)
d) i) Three chemistry students find a bottle of a colourless liquid in the laboratory and each makes a different suggestion about the identity of its contents.
I think it is an oxidising agent.
I think that it is neither an oxidising nor a reducing agent.
I think it is a reducing agent.
Complete the following table to summarise TWO different tests the students could use to find out whose suggestion is correct.
Test reagent
Josh’s suggestion is correct
Results of test if:
Richard’s suggestion is correct
Matthieu’s suggestion is correct
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[2]
JoshRichardMatthieu
[6]
ii) Assuming Matthieu’s suggestion is correct, explain the reason for the colour change he observed and suggest a second reagent he could use to confirm that he is correct.
Explanation: Reagent:
iii) Name one substance that behaves as both an oxidising agent and a reducing agent.
e) By referring to oxidation and reduction, explain EACH of the following statements.
i) The cut surface of an apple turns brown if the apple is left uneaten on a plate.
ii) Sodium chlorate(I) is a good bleaching agent.
iii) Sodium sulfite is a good preservative of some food items.
iv) Iron nails rust very easily when exposed to moist air.
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Total Marks
[2]
[1]
[1]
[1]
[2]
[1]
A9 Electrochemistry
1 a) i) Distinguish between a conductor and a non-conductor.
ii) Draw lines to classify EACH of the following substances as a conductor or a nonconductor.
sodium chloride
sulfate solution
b) i) What is an electrolyte?
ii) Distinguish between a strong and a weak electrolyte.
iii) Why is pure water classified as a weak electrolyte?
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[1]
copper(II)
aqueous
acid carbon tetrachloride sulfur conductor graphite non-conductor [3]
solid
nitric
[1]
[2]
[2]
iv) Complete the table below to give TWO differences between metallic conduction and electrolytic conduction.
Metallic conductionElectrolytic conduction
c) i) Define EACH of the following terms.
electrolysis:
anode: cathode:
ii) Why does oxidation occur at the anode and reduction occur at the cathode during electrolysis?
d) The diagram below shows the electrolysis of molten lead(II) bromide using inert graphite electrodes.
i) Label W, X, Y and Z on the lines provided on the diagram above.
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[4]
[3]
[2]
A W X Y Z molten lead(II) bromide crucible heat
[4]
c) How long must a steady current of 5·0 A flow through dilute sulfuric acid to produce 3·0 g of hydrogen at the cathode?
[relative atomic mass: H = 1]
5 a) i) What is the process of anodising used for?
ii) Suggest TWO reasons for anodising a saucepan.
b) i) James wishes to demonstrate the principles of electroplating a spoon with silver to his fellow students. What would he use as the anode, the cathode and the electrolyte?
the anode
the cathode
the electrolyte
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1.
[2]
2.
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A9 Electrochemistry (cont.)
ii) Write ionic equations for the reaction occurring at EACH electrode during the electroplating process: at the anode at the cathode
iii) Calculate the increase in mass of the spoon if James allows a current of 2·0 A to flow for 32 minutes and 10 seconds through the electrode.
c) i) Electrolysis can be used to purify metals. Briefly outline the method used to purify a lump of copper.
ii) Explain why electrolysis is not suitable for purifying metals above hydrogen in the electrochemical series.
Total Marks / 89
61
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[3]
[4]
[2]
A10 Rates of reaction
1 a) Define ‘rate of reaction’.
b) In the space provided, draw a labelled diagram to show how Keenan would have set up the apparatus to conduct his experiment.
c) Use the results to determine the average rate of the reaction in cm3 s–1:
i) in the first minute:
ii) in the second minute:
d) By referring to the collision theory for a reaction, explain why the average rate of the reaction was higher in the first minute than in the second minute.
e) Explain what happened after 180 s.
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[3]
[1]
[1]
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[1]
f) To determine how the rate of a reaction varies as the reaction proceeds, Keenan reacted calcium carbonate crystals with excess hydrochloric acid and measured the volume of carbon dioxide produced every 30 seconds. His results are in the table.
Plot Keenan’s results on the graph paper below.
2 a) List FOUR factors that affect the rate of a reaction.
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Time (s) Volume of carbon dioxide (cm3) 00 3054 6088 90106 120118 150126 180128 210128 240128
0306090120150 time (s) Volume of carbon dioxide (cm 3 ) 180210240 [3]
1. 2. 3. 4. [4]
A10 Rates of reaction (cont.)
b) To investigate the effect of changing various factors on the rate of a reaction, Kayla placed a conical flask onto a balance at room temperature and added 5·0 g of magnesium ribbon followed by excess hydrochloric acid of concentration 0·5 mol dm–3. She weighed the flask and its contents at regular intervals and plotted her results as shown:
i) Kayla repeated her experiment using 5·0 g of magnesium powder in place of the ribbon. Draw a second curve on the figure above to show the results of her second experiment. [2]
ii) By referring to collision theory for reactions, explain the gradient of the curve you drew in i).
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time mass of reaction
[2]
iii) Kayla repeated her experiment again at 400 C. What effect would you expect this to have had on the rate of the reaction? Explain your answer.
Effect:
Explanation:
iv) Kayla repeated her experiment again using excess hydrochloric acid of concentration 0·25 mol dm−3. What effect would you expect this to have had on the rate of the reaction? Explain your answer.
Effect:
Explanation:
c) i) What is a catalyst?
ii) How does a catalyst work to speed up a chemical reaction?
Total Marks /
65
31
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[3]
[1]
[2]
