Chemistry in Society
Metals
NAT 5
Homework Two
1. What is the name of the compound with the formula Ag2O?
A
Silver (i) Oxide
B
Silver (ii) Oxide
C
Silver (iii) Oxide
D
Silver (iv) Oxide
2.
2K+(aq) + 2I-(aq) +
Pb2+(aq) +
2NO3-(aq)
Pb2+(I-)2(s) + 2K+(aq) + 2NO3-(aq)
(a) The type of reaction represented by the ionic equation above is;
A
Addition
B
Neutralisation
C
Precipitation
D
REDOX
(b) The spectator ions present in this reaction are;
A
K+(aq)
and
NO3-(aq)
B
K+(aq)
and
I-(aq)
C
Pb2+(aq) and
NO3-(aq)
D
Pb2+(aq) and
I-(aq)
3. The ion-electron equation
Ti(s) → Ti2+(aq) + 2e-
A
Reduction of titanium atoms
B
Reduction of titanium ions
C
Oxidation of titanium atoms
D
Oxidation of titanium ions
4. Which metal would displace zinc from a solution of zinc sulphate solution?
A
Iron
B
Magnesium
C
Silver
D
Tin
5. Equations are used to represent chemical reactions.
A
Sn(s) → Sn2+(aq) + 2e-
B
Cu2+(aq) + 2e- → Cu(s)
C
H+(aq) + OH-(aq) → H2O(l)
D
2Mg(s) + O2(g) → 2MgO(s)
Which equation represents a reduction reaction?
6. In which of the test tubes would the iron nail corrode fastest?
7. Reactions can be represented by chemical equations.
A
Fe2+(aq) + 2e- → Fe(s)
B
Fe2+(aq) → Fe3+(aq) + e-
C
2H2(g) + O2(g) → 2H2O(l)
D
2H2O(l) +
O2(g) + 4e-
→ 4OH-(aq)
Identify the two equations that are involved in the corrosion of iron.
8. Electricity can be produced using electrochemical cells.
(a) Identify the arrangement that would not produce electricity.
(b) Identify the two cells that could be used to compare the reactivity of gold and
lead.
9. Four cells were made by joining copper, iron, tin and zinc to silver. The results
are shown in the table.
Which line in the table shows the voltage of the cell containing copper joined to
silver.
Cell
A
B
C
D
Voltage (v)
1.6
1.2
0.9
0.5
10.
Which of the following describes the reaction at the positive electrode?
A
I- Reduced
B
I- Oxidised
C
Pb2+ Reduced
D
Pb2+ Oxidised
11.
In the cell shown electrons flow through
A
The solution from Cu to Sn
B
The solution from Sn to Cu
C
The wires from Cu to Sn
D
The wires from Sn to Cu
12.
What is the purpose of the salt bridge?
A
To ensure electrons flow from Sn to Zn.
B
To complete the circuit through the flow of atoms.
C
To complete the circuit through the flow of electrons.
D
To complete the circuit through the flow of ions.
13. Molten iron is used to join railway lines together.
Molten iron is produced when aluminium reacts with iron oxide.
The equation for the reaction is:
2Al + Fe2O3 → 2Fe + Al2O3
(a) The formula for iron oxide is Fe2O3
What is the charge on this iron ion?
(b) Calculate the percentage by mass of iron in iron oxide.
14. Zinc displaces copper from copper(ii) sulphate solution.
The equation for the reactions is:
Zn(s) + Cu2+(aq) + SO42-(aq) → Zn2+(aq) + SO42-(aq) + Cu(s)
(a) Circle the spectator ion in the above equation.
(b) Write an ion-electron equation for the oxidation step in this reaction.
You may wish to use the data book to help you
(c) The reaction can also be carried out in a cell.
(i)
Complete the three labels on the diagram.
(ii)
What is the purpose of the ion bridge?
15. A student carried out an experiment to investigate the rusting of iron.
(a) Write the formula of the ion that turns ferroxyl indicator blue.
(b) Name the ion formed from water and oxygen, when they accept electrons during
rusting.
You may wish to use the data book to help you
(c) Explain why magnesium prevents iron from rusting.
16. When iron reacts with water and oxygen, rust forms.
(a) During rusting, iron initially loses two electrons to form iron(ii) ions. These are
further oxidised to form iron(iii) ions.
Write the ion-electron equation to show iron(ii) ions forming iron(iii) ions.
You may wish to use the data book to help you
(b) Some iron railings were fixed into stone walls by using plugs of lead. Over time,
the iron rails rusted faster at the point of contact with lead.
Why does lead increase the rate of rusting?
Why does lead increase the rate of rusting?
17. The voltage obtained when different metal strips are connected to copper in
a cell varies and this has led to the formation of the electrochemical series.
The results are shown.
Metal Strip
Voltage (v)
1
2
3
4
0.6
0.2
0.9
0.1
Direction of Electron
Flow
Metal 1 to copper
Copper to metal 2
Metal 3 to copper
Copper to metal 4
(a) Which of the metals used is highest in the electrochemical series?
(b) Which two of the metals used would produce the highest voltage when
connected into a cell?
(c) What would be the reading on the voltmeter if both strips of metal were
copper?
(d) Why can glucose solution not be used as an electrolyte?
18. A technician set up the following cell.
The reaction taking place at electrode B is:
2Br-(aq) → Br2(l) + 2e-
(a) On the diagram, clearly mark the path and direction of electron flow.
(b) Write an ion-electron equation for the reaction taking place at electrode A.
You may wish to use the data book to help you.
(c) Name the piece of apparatus labelled X.
19. Iron displaces silver from silver(i) nitrate solution.
The equation for the reaction is:
Fe(s) + 2Ag+(aq) + NO3-(aq) → Fe2+(aq) + 2Ag(s) +
NO3-(aq)
(a) Circle the spectator ion in the above equation.
(b) Describe a chemical test, including results, to show that Fe2+(aq) ions are formed.
(c) Write ion-electron equations for the reduction step in the reaction.
You may wish to use the data book to help you.
(d) This reaction can also be carried out in a cell.
Complete the three labels on the diagram.
20. A student carried out some experiments with four different metals and their metal
oxides.
The results are shown in the table.
Metal
w
x
y
z
Reaction with cold
water
No Reaction
No Reaction
Gas Produced
No Reaction
Reaction with dilute
acid
No Reaction
Gas Produced
Gas Produced
No Reaction
(a) Place the four metals in order of reactivity.
(b) Z is silver and W is copper.
Suggest names for X and Y.
Effect of heat on
metal oxide
No Reaction
No Reaction
No Reaction
Metal Produced
21. A student set up the cell shown.
The reaction taking place at electrode X is;
Br2(l) + 2e- → 2Br-(aq)
(a) Name the type of chemical reaction taking place at electrode X.
(b) On the diagram clearly mark the path and direction of electron flow.
(c) The ion-electron equation taking place at electrode Y is;
2I-(aq) → I2(s) + 2e-
Write the overall REDOX equation for this reaction.
22. In Australia flow cells are used to store energy from solar cells.
(a) The reaction taking place at electrode A when the cell is producing electricity
is;
Zn(s) → Zn2+(aq) + 2e-
Name the type of chemical reaction taking place at electrode A.
(b) By considering the ion-electron equation above, clearly mark on the diagram the
path and direction of electron flow.