Cambridge IGCSE Chemistry - 0620 - Supplement Paper 2 2017 Summer Zone 2

Small crystals of purple KMnO$_4$ ($M_r = 158$) and orange K$_2$Cr$_2$O$_7$ ($M_r = 294$) were placed at the centres of separate petri dishes filled with agar jelly. They were left to stand under the same physical conditions. After some time, the colour of each substance had spread out as shown.
The lengths of the arrows indicate the relative distances travelled by particles of each substance. Which statement is correct?

Impurities change the melting and boiling points of substances.
Sodium chloride is added to a sample of pure water.
How does the addition of sodium chloride affect the melting point and boiling point of the water?
[Table_1]

The diagram shows a chromatogram of four substances.
Which substance has an $R_f$ value of approximately 0.32?

Which element does not form a stable ion with the same electronic structure as argon?

Graphite and diamond are both forms of the element carbon.
Which row shows the number of other carbon atoms that each carbon atom is covalently bonded to in graphite and diamond?
[Table_1]

Which statement describes metallic bonding?

Which equations are balanced?
1 $ \quad \text{Fe}_{2}\text{O}_{3} + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_{2} $
2 $ \quad \text{ZnCO}_{3} + 2\text{HCl} \rightarrow \text{ZnCl}_{2} + \text{CO}_{2} + 2\text{H}_{2}\text{O} $
3 $ \quad \text{Mg(NO}_{3})_{2} + \text{NaOH} \rightarrow \text{Mg(OH)}_{2} + 2\text{NaNO}_{3} $
4 $ \quad \text{CaCO}_{3} + \text{H}_{2}\text{SO}_{4} \rightarrow \text{CaSO}_{4} + \text{H}_{2}\text{O} + \text{CO}_{2} $

Calcium carbide, CaC_2, reacts with water to form ethyne, C_2H_2, and calcium hydroxide.
The equation for the reaction is shown.
CaC_2(s) + 2H_2O(l) \rightarrow C_2H_2(g) + Ca(OH)_2(s)
Which volume of ethyne is produced when 6g of water react completely with calcium carbide?

Which statement about electrolysis is correct?

The reactivity series for a number of different metals is shown.
[Image_1: Reactivity series chart]
most reactive --> least reactive
magnesium | zinc | iron | copper | silver | platinum
The diagram shows different metal strips dipped into an electrolyte.
[Image_2: Diagram with metal strips and electrolyte]
Which pair of metals produces the highest voltage?

Which statement about fuels is correct?

Which statements about exothermic and endothermic reactions are correct?
1. During an exothermic reaction, heat is given out.
2. The temperature of an endothermic reaction goes up because heat is taken in.
3. Burning methane in the air is an exothermic reaction.

The equation for the reaction between hydrogen and chlorine is shown.
$$H_2(g) + Cl_2(g) \rightarrow 2HCl(g)$$
The reaction is exothermic.
The bond energies are shown in the table.
[Table_1]
What is the energy change for the reaction?

A gas is produced when calcium carbonate is heated. Which type of change is this?

A student was investigating the reaction between marble chips and dilute hydrochloric acid. [Image_1: Apparatus setup with a gas syringe, bung, marble chips, and 25 cm³ of dilute hydrochloric acid shown]
Which changes slow down the rate of reaction?
[Table_1: Changes with columns - temperature of acid, concentration of acid, surface area of marble chips:
A. decrease, decrease, decrease
B. decrease, decrease, increase
C. increase, decrease, decrease
D. increase, increase, increase]

The reaction used to manufacture ammonia from nitrogen and hydrogen is reversible. An equilibrium can be established between ammonia, nitrogen and hydrogen. Which statement describes the equilibrium?

An example of a redox reaction is shown.

$$ \text{Zn} + \text{Cu}^{2+} \rightarrow \text{Zn}^{2+} + \text{Cu} $$

Which statement about the reaction is correct?

Which type of oxide is aluminium oxide?

Which statements about a weak acid, such as ethanoic acid, are correct?
1. It reacts with a carbonate.
2. It does not neutralise aqueous sodium hydroxide solution.
3. It turns red litmus blue.
4. It is only partially ionised in aqueous solution.

Silver chloride is a white solid which is insoluble in water.
Which statement describes how a sample of pure silver chloride can be made?

Dilute sulfuric acid is added to two separate aqueous solutions, X and Y. The observations are shown.

[Table_1]

Which row shows the ions present in the solutions?

Which element is less reactive than the other members of its group in the Periodic Table?

The elements oxygen and sulfur are in the same group of the Periodic Table.
Which statement about oxygen and sulfur is not correct?

Why are weather balloons sometimes filled with helium rather than hydrogen?

Which process is involved in the extraction of zinc from zinc blende?

Element E:
• forms an alloy
• has a basic oxide
• is below hydrogen in the reactivity series.
What is E?

A list of metals is shown.

aluminium
copper
iron
magnesium
silver
zinc

Stainless steel is an alloy of iron and other metals. It is strong and does not rust but it costs much more than normal steel.
What is not made from stainless steel?

The diagram shows some uses of water in the home. For which uses is it important for the water to have been treated?

The carbon cycle includes the processes combustion, photosynthesis and respiration. Which row shows how each process changes the amount of carbon dioxide in the atmosphere?

[Table_1]

Which statement about the conditions used in the Haber process is not correct?

Which chemical reaction decreases pollution in the air?

Which statement about sulfuric acid is correct?

Statements about methods of manufacture and uses of calcium oxide are shown.
1. It is manufactured by reacting acids with calcium carbonate.
2. It is manufactured by heating calcium carbonate.
3. It is used to desulfurise flue gases.
4. It is used to treat alkaline soil.
Which statements are correct?

The industrial fractional distillation of petroleum is shown.

Which process happens at Y?

Which statement about homologous series is not correct?

The diagram shows part of the molecule of a polymer.

Which diagram shows the monomer from which this polymer could be manufactured?

Ethanol is manufactured by fermentation or by the catalytic addition of steam to ethene.
What is an advantage of ethanol manufacture by fermentation instead of by the catalytic addition of steam to ethene?

The formula of an ester is $\text{CH}_3\text{CH}_2\text{CH}_2\text{COOCH}_2\text{CH}_2\text{CH}_3$.
Which acid and alcohol react together to make the ester?
[Table_1]

Polyesters and polyamides are types of synthetic polymer.
Which statements are correct?
1. They are made by addition polymerisation.
2. They are made by condensation polymerisation.
3. The monomers from which they are made are unsaturated hydrocarbons.
4. The monomers from which they are made contain reactive functional groups at their ends.