Cambridge IGCSE Chemistry - 0620 - Supplement Paper 2 2017 Summer Zone 3

Small crystals of purple $\text{KMnO}_4$ ($M_r = 158$) and orange $\text{K}_2\text{Cr}_2\text{O}_7$ ($M_r = 294$) 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?

A compound, X, has a melting point of 71°C and a boiling point of 375°C. Which statement about X is correct?

A student used chromatography to analyse a green food colouring. The chromatogram obtained is shown.
The table lists some yellow food dyes and their $R_f$ values.
Which yellow food dye does the green food colouring contain?
[Table_1]

The electronic structures of atoms Q and R are shown.



Q and R form an ionic compound.

What is the formula of the compound?

Which substance is a macromolecule?

The diagram shows metallic bonding.

Which labels are correct?
[Table_1]

Aqueous iron(III) sulfate and aqueous sodium hydroxide react to give a precipitate of iron(III) hydroxide and a solution of sodium sulfate. What is the balanced equation for this reaction?

The equation for the reaction between sodium carbonate and dilute hydrochloric acid is shown.
\[ \text{Na}_2\text{CO}_3 + 2\text{HCl} \rightarrow 2\text{NaCl} + \text{H}_2\text{O} + \text{CO}_2 \]
What is the maximum volume of carbon dioxide produced when 26.5 g of sodium carbonate react with dilute hydrochloric acid?

Which statement about electrolysis is correct?

The reactivity series for a number of different metals is shown.
[Table_1]
The diagram shows different metal strips dipped into an electrolyte.

Which pair of metals produces the highest voltage?

Heat energy is produced when hydrocarbons burn in air. Which equations represent this statement?

1. $\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}$
2. $\text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O}$
3. $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$

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.

Hydrogen and chlorine react to form hydrogen chloride.
The reaction is exothermic.
$$\text{H}_2(g) + \text{Cl}_2(g) \rightarrow 2\text{HCl}(g)$$
The overall energy change for this reaction is $-184\, \text{kJ/mol}$.
The table gives some of the bond energies involved.

[Table_1]

What is the energy of the \(\text{Cl-Cl}\) bond?

Which changes are physical changes?
1. melting ice to form water
2. burning hydrogen to form water
3. adding sodium to water
4. boiling water to form steam

A student was investigating the reaction between marble chips and dilute hydrochloric acid.
Which changes slow down the rate of reaction?

Hydrogen is produced when methane reacts with steam.
The equation for the reaction is shown.
$$\text{CH}_4(g) + \text{H}_2\text{O}(g) \rightleftharpoons \text{CO}(g) + 3\text{H}_2(g)$$
The forward reaction is endothermic.
Which conditions produce the highest yield of hydrogen?
[Table_1]

An example of a redox reaction is shown.
Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu
Which statement about the reaction is correct?

Which oxide is amphoteric?

Chloric(I) acid, $\text{HClO}$, is formed when chlorine dissolves in water. It is a weak acid. What is meant by the term weak acid?

Silver nitrate reacts with sodium chloride to produce silver chloride and sodium nitrate. The equation for the reaction is shown.
$\text{AgNO}_3(\text{aq}) + \text{NaCl}(\text{aq}) \rightarrow \text{AgCl}(\text{s}) + \text{NaNO}_3(\text{aq})$
How is silver chloride separated from the reaction mixture?

Aqueous sodium hydroxide reacts with an aqueous solution of compound Y to give a green precipitate.
Aqueous ammonia also reacts with an aqueous solution of compound Y to give a green precipitate.
In each case the precipitate is insoluble when an excess of reagent is added.
Which ion is present in Y?

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

Ununseptium (atomic number 117) is a man-made element that is below astatine in Group VII of the Periodic Table.
What is the expected state of ununseptium at room temperature?

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

Which equation from the zinc extraction process shows the metal being produced by reduction?

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

The section of the reactivity series shown includes a newly discovered element, symbol X.
The only oxide of X has the formula XO.

Ca
Mg
Fe
X
H
Cu
Which equation shows a reaction which occurs?

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 describes how carbon dioxide gas is added to or removed from the atmosphere.
Which row describes the movement of carbon dioxide during each process?
[Table_1]

Which row gives the catalyst for the Haber process and the sources of the raw materials?
[Table_1]

Petrol burns in a car engine to produce waste gases which leave through the car exhaust. One of these waste gases is an oxide of nitrogen. Which statement describes how this oxide of nitrogen is formed?

Which statement about sulfuric acid is correct?

Two equations are shown.
reaction 1 $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$
reaction 2 $\text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2$
Which terms describe reactions 1 and 2?

Fuel oil, gasoline, kerosene, and naphtha are four fractions obtained from the fractional distillation of petroleum. What is the order of the boiling points of these fractions? [Table_1]

Butane and methylpropane are isomers with molecular formula $C_4H_{10}$.
Which statements are correct?
1. They have similar chemical properties.
2. They have the same general formula.
3. They have the same structural formula.

The diagram shows part of the molecule of a polymer.

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

Ethanol can be produced by fermentation or by the catalytic addition of steam to ethene. Which row shows an advantage and a disadvantage for each process?
[Table_1]

The structure of an ester is shown.

Which alcohol and carboxylic acid produce this ester?

How can the amino acids in a protein be separated and identified?