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Chemistry Time allowed: 1 hour
Paper 2 Theory Total Marks: /45
Name: ___________________________________
______________________________________________________________________________
Read These Instructions First
Answer on the question paper. No extra paper is required.
Write in dark blue or black pen. You may use a lead pencil for any diagrams or graphs.
Electronic calculators may be used.
You may lose marks if you do not show your working or if you do not use appropriate units.
A periodic table is provided at the end of the paper.
Good Luck!
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1. Choose from the particles shown to answer the questions.
Each particle can be used once, more than once or not at all.
a. Which particle has only 20 protons in its nucleus?
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b. Which particle has a nucleon number of 35?
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c. Which particle has an electronic structure of 2.8.8?
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d. Which particle is an atom with only 10 neutrons in its nucleus?
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e. Which particle is an atom of a transition element?
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2. The table shows some of the properties of the elements in Group II of the Periodic Table.
a. Explain why the elements in Group II have similar chemical properties.
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b. Explain why it is easier to predict the atomic radius of radium, Ra, than the melting
point of radium
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c. Magnesium chloride contains Mg2+ and Cl- ions.
i. Write the electronic configuration for a magnesium ion.
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ii. Magnesium is produced by the electrolysis of molten magnesium chloride.
Construct equations for the reactions taking place at the:
Negative Electrode____________________________
Positive Electrode______________________________ [2]
d. Magnesium reacts with aqueous copper(II) sulfate in a redox reaction.
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Mg(s) + Cu2+(aq) --------˃ Mg2+(aq) + Cu(s)
Which particle is reduced?______________________________________________ [1]
Explain your answer_____________________________________________________
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e. Magnesium reacts with steam. Name the products of this reaction.
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f. Calcium reacts with cold water. Write the equation for this reaction.
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g. Magnesium chloride is a soluble salt. Describe how a pure sample of magnesium
chloride crystals can be made from magnesium.
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[4]
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3. Dry air contains nitrogen, oxygen, argon and other gases.
a. State the percentage compositions by volume of nitrogen and oxygen present in dry air
Nitrogen_____________________%
Oxygen______________________% [1]
b. The formula for aqueous magnesium hydroxide is Mg(OH)2.
Draw a ‘dot-and-cross’ diagram of an oxygen molecule. Show only the outer shell
electrons.
[2]
c. What is the formula of argon gas?
___________________________________________________________________ [1]
d. Titanium is extracted from titanium(IV) chloride by reduction with molten sodium in
an argon atmosphere and not in air.
Suggest why this reaction is carried out in an argon atmosphere and not in air.
_____________________________________________________________________
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e. State one other use of argon.
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4. Copper(II) sulfate is an ionic compound.
a. Describe the arrangement of the ions and the type of attractive forces between the ions
in solid copper(II) sulfate.
Arrangement___________________________________________________________
Type of attractive forces________________________________________________ [2]
b. Explain why solid copper(II) sulfate does not conduct electricity but aqueous copper(II)
sulfate does conduct.
______________________________________________________________________
______________________________________________________________________
___________________________________________________________________ [2]
c. When aqueous copper(II) sulfate is electrolyzed using platinum electrodes, copper(II)
ions are reduced to copper at the negative electrode. Oxygen is formed at the positive
electrode by loss of electrons from hydroxide ions.
i. State the source of the hydroxide ions.
_____________________________________________________________ [1]
ii. Complete the equation for the reaction at the positive electrode.
____+OH- ------˃ O2 + ______H2O + ________ [1]
iii. Suggest why hydroxide ions and not sulfate ions are discharged at the positive
electrode.
________________________________________________________________
_____________________________________________________________ [1]
d. Answer the following:
i. Give the formulae of the four ions present in aqueous copper(II) sulfate
_____________________________________________________________ [1]
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ii. Suggest why the solution becomes acidic as the electrolysis proceeds.
________________________________________________________________
_____________________________________________________________ [2]
iii. Suggest why the blue color of the aqueous copper(II) sulfate fades as the
electrolysis proceeds.
________________________________________________________________
_____________________________________________________________ [2]
e. Draw a ‘dot-and-cross’ diagram of an oxygen molecule.
Show only the outer shell electrons.
[2]
5. The diagram shows the structure of a metal.
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a. Refer to this structure to explain why
i. metals are malleable,
________________________________________________________________
_____________________________________________________________ [2]
ii. Metals conduct electricity.
_____________________________________________________________ [1]
b. The table shows the ease with which different metal oxides can be reduced.
Use the information in the table to place the metals calcium, iron, silver and titanium in
order of their reactivity.
c. Explain in terms of structure and bonding why diamond has such a high melting point.
______________________________________________________________________
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___________________________________________________________________ [2]
d. Lead oxide is an amphoteric oxide. What is the meaning of the term amphoteric?
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