Cambridge IGCSE Chemistry - 0620 - Supplement Paper 2 2015 Summer Zone 3

A sugar cube is dropped into a hot cup of tea.
The tea is not stirred.
Which statement explains why the tea becomes sweet?
A The heated water molecules penetrate the sugar cube.
B The hot tea causes the sugar to melt.
C The sugar cube dissolves and its molecules diffuse.
D The sugar molecules get hot and evaporate.

A blue solid, X, is soluble in water.
Which method is used to obtain pure solid X from an aqueous solution?
A chromatography
B crystallisation
C filtration
D neutralisation

Two atoms, X and Y, can be represented as shown. $$ ^{41}_{20}\text{X} quad ^{45}_{20}\text{Y} $$ Which statement is not correct?
A. X and Y are atoms of different elements.
B. X and Y are isotopes.
C. X and Y have different mass numbers.
D. X and Y have the same number of electrons.

Two atoms have the same relative atomic mass but different chemical properties.
Which row about the proton and neutron numbers of these atoms is correct?

[Table]
| | proton numbers | neutron numbers |
|---------|----------------|-----------------|
| A | different | different |
| B | different | same |
| C | same | different |
| D | same | same |

Which statements comparing the properties of electrons, neutrons and protons are correct?

[Table_1]

Diamond and graphite are both macromolecules.

Which statement is not correct?
A Diamond and graphite contain carbon atoms only.
B Diamond and graphite contain charged ions.
C Diamond and graphite have high melting points.
D The atoms in diamond and graphite are held together by covalent bonds.

In which compounds are pairs of electrons shared between atoms?
1. methane
2. lead bromide
3. sodium chloride

A. 1 only
B. 2 only
C. 1 and 3
D. 1, 2 and 3

Aluminium oxide has the formula $Al_2O_3$.
Which statement about aluminium oxide is correct?
A 2g of aluminium atoms are combined with 3g of oxygen atoms.
B 2g of aluminium atoms are combined with 3g of oxygen molecules.
C Aluminium oxide has a relative molecular mass of 102.
D Pure aluminium oxide contains a higher mass of oxygen than of aluminium.

Copper and hydrogen can each be formed by electrolysis. At which electrodes are these elements formed?
[Table_1]

An object is electroplated with silver using an aqueous silver salt as the electrolyte.
Which set of conditions is used?
[Table_1]
| the object to be electroplated is the | the other electrode is made from |
|-------------------------------------|-----------------------------------|
| A | anode | carbon |
| B | anode | silver |
| C | cathode | carbon |
| D | cathode | silver |

Which substance does not use oxygen to produce energy?
A coal
B hydrogen
C natural gas
D uranium

In which change is $N_2O_3$ oxidised?
[Image: Diagram showing pathways A: $N_2O_4 \to N_2O_3$, B: $N_2 \to N_2O_3$, C: $N_2O_3 \to N_2O$, D: $N_2O_3 \to NO$]

When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue.
$$\text{CoCl}_2.6\text{H}_2\text{O} \rightleftharpoons \text{CoCl}_2 + 6\text{H}_2\text{O}$$
What happens when water is added to the blue solid?

[Table_1]
colour | temperature
A | changes to pink | decreases
B | changes to pink | increases
C | remains blue | decreases
D | remains blue | increases

The diagram shows an experiment to measure the rate of a chemical reaction.
Which change decreases the rate of reaction?
A adding water to the flask
B heating the flask during the reaction
C using more concentrated acid
D using powdered metal

Which reaction is \textit{not} characteristic of an acid?
A It dissolves magnesium oxide.
B It produces ammonia from ammonium compounds.
C It produces carbon dioxide from a carbonate.
D It produces hydrogen from zinc metal.

Hydrochloric acid is used to clean metals.
The acid reacts with the oxide layer on the surface of the metal, forming a salt and water.
Which word describes the metal oxide?
A alloy
B base
C element
D indicator

Which of the following methods are suitable for preparing both zinc sulfate and copper sulfate?
1. Reacting the metal oxide with warm dilute aqueous sulfuric acid.
2. Reacting the metal with dilute aqueous sulfuric acid.
3. Reacting the metal carbonate with dilute aqueous sulfuric acid.
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3

Which gas relights a glowing splint?
A. ammonia
B. carbon dioxide
C. hydrogen
D. oxygen

The noble gases, which are in Group 0 of the Periodic Table, are all very .......1....... .
.......2......., one of these gases, is used to provide an inert atmosphere in lamps.
Another, .......3......., is used for filling balloons because it is less dense than air.

Which words complete the sentences about noble gases?

[Table_1]

\begin{table} \begin{tabular}{|c|c|c|c|} \hline & 1 & 2 & 3 \\ \hline A & reactive & argon & helium \\ \hline B & reactive & helium & argon \\ \hline C & unreactive & argon & helium \\ \hline D & unreactive & helium & argon \\ \hline \end{tabular} \end{table}

Which properties of the element titanium, Ti, can be predicted from its position in the Periodic Table?
[Table_1]:
| | can be used as a catalyst | conducts electricity when solid | has low density | forms coloured compounds |
|-----------------|---------------------------|---------------------------------|-----------------|--------------------------|
| A | ✓ | ✓ | ✓ | ✗ |
| B | ✓ | ✓ | ✗ | ✓ |
| C | ✓ | ✗ | ✓ | ✓ |
| D | ✗ | ✓ | ✓ | ✓ |

X is a Group I metal.
Y and Z are Group VII elements.

When X reacts with Y a salt is formed. A solution of this salt reacts with Z to form a different salt.

What are X, Y and Z?

[Table_1]

In the outline of the Periodic Table below, some elements are shown as numbers.
Which two numbers are metals in the same period?
A 1 and 2 B 1 and 7 C 3 and 5 D 5 and 6

The diagrams show the structure of two substances used to make electrical conductors.

Which statement correctly describes X and Y?
A X is a pure metal and Y is a compound.
B X is a pure metal and Y is an alloy.
C X is a solid and Y is a liquid.
D X is harder and stronger than Y.

Which statement about the uses of aluminium, mild steel and stainless steel is correct?
A. Aluminium is used for food containers as it has a high density.
B. Mild steel is used for car bodies as it is resistant to corrosion.
C. Stainless steel is used for aircraft bodies as it is strong.
D. Stainless steel is used for cutlery as it is resistant to corrosion.

Which row describes the conditions used to make steel from the iron produced by a blast furnace?
[Table_1]
Table 1: Conditions used to make steel
| | calcium oxide (lime) | oxygen | heat |
|---------------------|---------------------|--------|------|
| A | ✓ | ✓ | ✓ |
| B | ✓ | ✓ | ✗ |
| C | ✗ | ✓ | ✓ |
| D | ✗ | ✓ | ✗ |

The statements describe how different metals react with cold water.
• Calcium sinks, fizzing and releasing a steady stream of hydrogen.
• Copper does not react.
• Sodium floats, fizzing and rapidly releasing hydrogen.
• Zinc does not react but does react with steam, releasing hydrogen.

Using the information, where should hydrogen be placed in the reactivity series?
A below copper
B between sodium and calcium
C between calcium and zinc
D between zinc and copper

The diagram shows stages in producing drinking water.
In which tank is chlorine added to the water?

Oxygen is a reactive element.
Which row shows which of oxygen’s reactions are useful?

[Table_1:
| | fuel combustion | rusting | steel manufacture |
|----|----------------|---------|-------------------|
| A | no | no | yes |
| B | no | yes | no |
| C | yes | no | yes |
| D | yes | yes | no | ]

Which combination of chemical compounds could be used to produce the fertiliser shown?
[Image_1: Fertiliser Bag with Label 'NPK 21:16:8 SUPERGROW']
A. $(NH_4)_3PO_4, KCl$
B. $NH_4NO_3, Ca_3(PO_4)_2$
C. $NH_4NO_3, CO(NH_2)_2$
D. $NH_4NO_3, K_2SO_4, (NH_4)_2SO_4$

Below are two statements about sulfur dioxide.
1. Sulfur dioxide is formed when fossil fuels burn and it is an acidic oxide.
2. Sulfur dioxide is one of the gases in the air which is responsible for ‘acid rain’.
Which is correct?
A. Both statements are correct and statement 1 explains statement 2.
B. Both statements are correct but statement 1 does not explain statement 2.
C. Statement 1 is correct but statement 2 is incorrect.
D. Statement 2 is correct but statement 1 is incorrect.

Which method is not used for rust prevention? A. coating working parts of industrial machinery with oil B. covering wire for gardening use with plastic C. immersing gardening tools in water for storage D. painting car bodies

Carbon dioxide and methane are ‘greenhouse gases’ which contribute to global warming.
Which process does not increase global warming?

A burning fossil fuels
B decay of organic waste
C farming cattle for beef
D growing crops such as sugar cane

Four reactions produce carbon dioxide.
1 respiration
2 fermentation
3 combustion of methane
4 manufacture of lime

Which reactions do not use oxygen from the air?
A 1 and 2
B 1 and 3
C 2 and 4
D 3 and 4

The diagram shows a kiln used to manufacture lime.
Which row identifies X and Y?
[Table_1]
X: lime, lime, limestone, limestone
Y: carbon dioxide, steam, carbon dioxide, steam

Which statement about the names of organic compounds is correct?
A. Compounds containing C=C double bonds are alkanes.
B. The compound of formula $CH_3CO_2H$ is methanoic acid.
C. The compound of formula $C_2H_4$ is ethane.
D. The compound of formula $C_2H_5OH$ is an alcohol.

Which statement about petroleum is not correct?
A It can be separated into useful substances by fractional distillation.
B It consists mainly of hydrocarbons.
C It is found underground in many parts of the world.
D Its main use is for making lubricants and polishes.

Ethene, propene and butene are all members of the same homologous series.
Which statement explains why ethene, propene and butene have similar chemical properties?
A. They all have the same functional group.
B. They are all gases at room temperature.
C. They are all hydrocarbons.
D. They are all organic.

Which statement describes the compound shown below?

A It is a colourless flammable gas.
B It is a liquid which decolourises bromine water.
C It is a liquid with a characteristic smell.
D It is formed when ethane reacts with steam.

A hydrocarbon A is cracked to make B and hydrogen.
Compound C is formed by the addition polymerisation of B.
To which homologous series do A, B and C belong?
[Table_1]

Ethanol is manufactured from petroleum by reacting ethene with steam. Which statements about this process are correct?
1. Ethene is obtained from the cracking of alkanes.
2. The process is carried out in the presence of yeast.
3. The reaction is an addition reaction.
4. The rate of reaction is increased by a catalyst.
A. 1 and 3 only
B. 1 and 4 only
C. 1, 2 and 3
D. 1, 3 and 4