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

The diagram shows a sugar lump in a cup of tea.



Which two processes must happen to spread the sugar evenly in the tea?

The results of some tests on a colourless liquid X are shown.
• Boiling point = 102°C
• Universal Indicator turns green

What is X?

A ethanol
B hydrochloric acid
C pure water
D sodium chloride (salt) solution

The atomic structures of four particles are shown.

[Table_1]

Which two particles are isotopes?
A W and X
B W and Y
C X and Z
D Y and Z

Q^{+} is an ion of element Q.
What has the highest value in the ion?
A the nucleon number
B the number of electrons
C the number of neutrons
D the proton number

Which statements comparing the properties of electrons, neutrons and protons are correct?
[Table_1: Begin]
neutrons and protons are both heavier than electrons | only electrons and neutrons are charged
A ✓ | ✓
B ✓ | ✗
C ✗ | ✓
D ✗ | ✗
[Table_1: End]

Graphite is a form of carbon.
Why can graphite be used as a lubricant?
A. Graphite contains delocalised electrons which move throughout the structure.
B. Graphite contains weak covalent bonds so the atoms move easily.
C. Graphite has a low melting point so it easily turns into a liquid.
D. Graphite has weak forces of attraction between layers so they can move.

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

A molecule, Z, contains two atoms of oxygen, six atoms of hydrogen and three atoms of carbon.

What is the formula of Z?

A) CH$_3$CH$_2$CHO
B) CH$_3$COCH$_3$
C) C$_2$H$_5$CO$_2$H
D) C$_3$H$_6$CO$_2$H

Copper and hydrogen can each be formed by electrolysis. At which electrodes are these elements formed?
[Table_1]
Table:
| | copper | hydrogen |
|--------|---------|----------|
| A | anode | anode |
| B | anode | cathode |
| C | cathode | anode |
| D | cathode | cathode |

The diagram shows the electroplating of a steel object. A student made the following statements.
1 The object turns a reddish-brown colour.
2 The copper sulfate solution changes to a paler blue colour.
3 The copper electrode becomes smaller.
Which statements are correct?
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only

The elements hydrogen and uranium are used as fuels.
The compound ethanol is also used as a fuel.
Which fuels require oxygen in order to produce heat energy?
[Table_1]

In which equation does the oxidation of the underlined compound occur?
A. $2CuO + \underline{C} \rightarrow CO_2 + \underline{Cu}$
B. $Fe_2O_3 + \underline{3CO} \rightarrow 2Fe + 3CO_2$
C. $2Mg + O_2 \rightarrow \underline{2MgO}$
D. $\underline{MnO_2} + 4HCl \rightarrow MnCl_2 + 2H_2O + \underline{Cl_2}$

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]

A simple way of making bread includes

1. Mixing flour with a small amount of yeast and some water to make a ‘dough’.
2. Leaving the dough in a warm place for the yeast to act on the dough to form carbon dioxide which increases the volume of the dough.

Which factors affecting a reaction rate are involved in bread making?

[Table_1]

| | temperature | use of an enzyme |
|----------|-------------|------------------|
| A | ✓ | ✓ |
| B | ✓ | ✗ |
| C | ✗ | ✓ |
| D | ✗ | ✗ |

Which statement is not correct?
A When a base reacts with an ammonium salt, ammonia is given off.
B When an acid reacts with a base, neutralisation takes place.
C When an acid reacts with a carbonate, carbon dioxide is given off.
D When the acidity of a solution increases, the pH increases.

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 method is used to make the salt copper sulfate?
A. dilute acid + alkali
B. dilute acid + carbonate
C. dilute acid + metal
D. dilute acid + non-metal oxide

Two tests are carried out to identify an aqueous solution of X.
test 1 Aqueous sodium hydroxide is added and a blue precipitate is produced.
test 2 Dilute nitric acid is added followed by aqueous silver nitrate and a white precipitate is produced.
What is X?
A copper carbonate
B copper chloride
C iron(III) carbonate
D iron(III) chloride

The positions of four elements in the Periodic Table are shown.
Which element does not form a compound with chlorine?

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

The table shows some properties of the Group I metals.

[Table_1]
| metal | melting point/°C | hardness | reaction with water |
|-------|-----------------|----------|--------------------|
| lithium | 181 | moderately soft | steady effervescence |
| sodium | 98 | soft | vigorous effervescence |
| potassium | 63 | very soft | very vigorous effervescence |
| rubidium | ? | ? | ? |

What are the properties of rubidium?

A melts below 63 °C, very soft, reacts explosively with water
B melts below 63 °C, very soft, reacts slowly with water
C melts above 181 °C, very soft, reacts explosively with water
D melts above 181 °C, very soft, reacts slowly with water

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

Which diagram represents an alloy? [Image diagrams: A, B, C, D]

Which statement is not correct?
A. Aluminium is used in food containers because of its resistance to corrosion.
B. Aluminium is used in the manufacture of aircraft because of its strength and low density.
C. Mild steel is used in car bodies because of its strength and low density.
D. Stainless steel is used in chemical plant because of its strength and resistance to corrosion.

Which row describes the conditions used to make steel from the iron produced by a blast furnace?

[Table_1]

Table_1:
| | calcium oxide (lime) | oxygen | heat |
|------------|----------------------|--------|------|
| A | ✓ | ✓ | ✓ |
| B | ✓ | ✓ | ✗ |
| C | ✗ | ✓ | ✓ |
| D | ✗ | ✓ | ✗ |

Samples of five different metals, E, F, G, H, and J were reacted with dilute sulfuric acid using the apparatus shown.

The volume of hydrogen gas collected after one minute was measured. The results are shown on the bar chart.

What is the order of reactivity of the metals (most reactive first)?
A. E, F, G, H, J
B. G, E, H, F, J
C. J, F, H, E, G
D. J, H, G, F, E

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

Which gas is not present in a sample of clean air?
A. carbon dioxide
B. chlorine
C. oxygen
D. water vapour

Which combination of chemical compounds could be used to produce the fertiliser shown?
[Image_1: Fertiliser bag with N P K 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. $NH_4NO_3$, $K_2SO_4$, $(NH_4)_2SO_4$

Carbon monoxide is given out from the exhaust of vehicles that burn fossil fuels.

Which row shows why carbon monoxide is a pollutant?

[Table_1]

A steel bicycle which had been left outdoors for several months was starting to rust. What would not reduce the rate of corrosion?
A Remove the rust and paint the bicycle.
B Remove the rust and store the bicycle in a dry shed.
C Remove the rust and wipe the bicycle with a clean damp cloth.
D Remove the rust and wipe the bicycle with an oily cloth.

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

A zinc compound forms carbon dioxide in two different reactions.
1 It is heated strongly.
2 It is added to hydrochloric acid.
Which type of reaction occurs in 1 and 2?

| | 1 | 2 |
|- |-----------------------|-----------------|
|A | combustion | neutralisation |
|B | combustion | oxidation |
|C | thermal decomposition | neutralisation |
|D | thermal decomposition | oxidation |

Substance X is used to treat industrial waste. [Image_1: Diagram showing industrial waste with pH 4 entering a container with X, resulting in treated waste with pH 7]
What is X and which type of reaction occurs during the treatment?
[Table_1: Option A: X = calcium oxide (lime), type of reaction = neutralisation Option B: X = calcium oxide (lime), type of reaction = redox Option C: X = carbon, type of reaction = neutralisation Option D: X = carbon, type of reaction = redox]

An organic compound has the molecular structure shown.
Which type of organic compound is this?
A. alcohol
B. alkane
C. alkene
D. carboxylic acid

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.

The structures of four different organic compounds are shown.

How many different homologous series are represented by these compounds?
A 1    B 2    C 3    D 4

The structure of a compound, Y, is shown. [Image_1: Structure of compound Y] Which row describes some of the physical properties of Y? [Table_1] | | colourless | characteristic smell | dissolves in water | |---|------------|----------------------|---------------------| | A | no | no | no | | B | no | no | yes | | C | yes | yes | no | | D | yes | yes | yes |

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]
alkene | alkane
A | B and C
B | A and C
C | A and B
D | A and C

Which row correctly describes the production of ethanol and its properties?
[Table_1]

which consists of:

| | can be made from glucose | can be made from ethene | is used as a fuel | is used as a solvent |
|-----------------------|---------------------------|------------------------|-------------------|---------------------|
| A | ✓ | ✓ | ✓ | ✓ |
| B | ✓ | ✗ | ✓ | ✓ |
| C | ✗ | ✓ | ✓ | ✗ |
| D | ✗ | ✓ | ✗ | ✓ |