Cambridge IGCSE Chemistry - 0620 - Supplement Paper 2 2018 Summer Zone 3

Ammonia gas is reacted with hydrogen chloride gas using the apparatus shown.

Solid ammonium chloride is produced.



Which statement explains why the solid ammonium chloride is formed nearer to the hydrogen chloride?

Paper chromatography is done in the same way with three different mixtures of dyes. Each mixture contains at least one of the dyes W, X, Y and Z.

The $R_f$ values of the dyes in the three mixtures are shown.

[Table_1]

Which conclusion is correct?

Solid R reacted with dilute sulfuric acid.
The initial temperature of the dilute sulfuric acid and the final temperature of the solution are shown.

What was the change in temperature in °C?

The 'lead' in a pencil is made of a mixture of graphite and clay.

When the percentage of graphite is increased, the pencil slides across the paper more easily.
Which statement explains this observation?

Iron has an atomic number of 26. It occurs as the isotopes $^{54}\text{Fe}$, $^{56}\text{Fe}$, $^{57}\text{Fe}$ and $^{58}\text{Fe}$.
Which statement explains why these isotopes have the same chemical properties?

How many silicon atoms are bonded to each oxygen atom in a crystal of silicon(IV) oxide?

Which substance is not a macromolecule?

An experiment was done to determine the formula of a hydrocarbon, $C_xH_y$.
10 cm³ of the gaseous hydrocarbon, $C_xH_y$, was burned in an excess of oxygen to form 20 cm³ of carbon dioxide and 30 cm³ of water vapour.
What is $C_xH_y$?

4.00 g of solid sodium hydroxide is added to water to make a solution with a concentration of 0.200 mol/dm^3.
What is the volume of water used?

Aqueous copper(II) sulfate is electrolysed using copper electrodes.
Which statement is correct?

Dilute sulfuric acid is electrolysed using inert electrodes.
What are the ionic half-equations for the reactions that take place at each electrode?
[Table_1]

Information about two reactions is given.
• The neutralisation reaction between citric acid and sodium hydrogencarbonate is endothermic.
• The displacement reaction between magnesium and carbon dioxide is exothermic.
Which statements about the two reactions are correct?
1. The energy of the products formed in the neutralisation reaction is greater than the energy of the reactants.
2. The energy of magnesium and carbon dioxide is greater than the energy of magnesium oxide and carbon.
3. In an exothermic reaction, the energy required to break the bonds is greater than the energy released when the new bonds are formed.

Ethene reacts with hydrogen. The equation is shown.

$$\text{CH}_2=\text{CH}_2 + \text{H}_2 \rightarrow \text{C}_2\text{H}_6$$

The bond energies are shown in the table. The reaction is exothermic.

[Table_1]

What is the energy change for the reaction?

Which row describes the effects of increasing both concentration and temperature on the collisions between reacting particles?

In the Contact process, sulfur dioxide is converted into sulfur trioxide in a reversible reaction.
$$2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$$
The forward reaction is exothermic.
Which conditions give the highest yield of sulfur trioxide at equilibrium?
[Table_1]

The equation for a redox reaction is shown. $2\text{Fe}^{3+} + \text{Zn} \rightarrow 2\text{Fe}^{2+} + \text{Zn}^{2+}$
Which statements are correct?
1. Fe³⁺ is reduced to form Fe²⁺.
2. Zn oxidises the Fe³⁺ ions.
3. Fe³⁺ is an oxidising agent.

Which statement about oxides is correct?

The equation represents an equilibrium in aqueous ammonia.
$$\text{NH}_3(\text{aq}) + \text{H}_2\text{O}(l) \rightleftharpoons \text{NH}_4^+(\text{aq}) + \text{OH}^-(\text{aq})$$
How does aqueous ammonia behave in this reaction?

An excess of aqueous sodium sulfate was added to aqueous barium chloride and the mixture was filtered.
Which row shows the identity of the residue and the substances present in the filtrate?
[Table_1]

Which methods are suitable for preparing \textbf{both} zinc sulfate and copper(II) 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

Which element is classified as a non-metal in the Periodic Table?

Part of the Periodic Table is shown.
Element Q has a low boiling point, low density and does not conduct electricity.
Which element is Q?

Which row describes a typical transition element?
[Table_1]

Which diagram represents a solid alloy?

The ionic equations for four reactions are shown.

$Z + X^{2+} \rightarrow Z^{2+} + X$
$Z + 2W^{+} \rightarrow Z^{2+} + 2W$
$X + 2W^{+} \rightarrow X^{2+} + 2W$
$Y + Z^{2+} \rightarrow Y^{2+} + Z$

What is the order of reactivity of the four metals, W, X, Y and Z?

[Table_1]

Which equation represents the first stage in the extraction of zinc from zinc blende?

Which statement explains why aluminium is used to manufacture aircraft?

Dry air is passed over hot copper until all the oxygen has reacted.

The volume of gas at the end of the reaction is 120 cm³.
What is the starting volume of dry air?

A steel bicycle which had been left outdoors for several months was starting to rust. What would not reduce the rate of corrosion?

Which statements about water are correct?
1. Household water contains dissolved salts.
2. Water for household use is filtered to remove soluble impurities.
3. Water is treated with chlorine to kill bacteria.
4. Water is used in industry for cooling.

Ammonia is manufactured by reacting hydrogen with nitrogen in the Haber process.
Which row describes the sources of hydrogen and nitrogen and the conditions used in the manufacture of ammonia in the Haber process?
[Table]

Which statements about the carbon cycle are correct?
1. Carbon dioxide is added to the atmosphere by respiration.
2. Carbon dioxide is added to the atmosphere by combustion of coal.
3. Carbon dioxide is removed from the atmosphere by photosynthesis.

Element Z forms an oxide, ZO₂. Three uses of ZO₂ are listed:
• bleaching agent
• killing bacteria
• manufacturing an important acid
What is Z?

Limestone is an important material with many uses. Limestone is heated to produce ......1...... and carbon dioxide. This reaction is called ......2...... . Which words correctly complete gaps 1 and 2? [Table_1]

What is not the correct use of the fraction named?

[Table_1]

Methane, ethane and propane belong to a family of hydrocarbons called alkanes.
What is the general formula of an alkane?

Which substances can be obtained by cracking hydrocarbons?

Which row describes an advantage and a disadvantage of making ethanol by fermentation?
[Table_1]

Which esters have the molecular formula $C_5H_{10}O_2$?
1. ethyl propanoate
2. propyl ethanoate
3. butyl methanoate
4. methyl butanoate

A polymer linkage contains carbon, hydrogen, nitrogen and oxygen atoms.
Which row about the polymer is correct?
[Table_1]