IGCSE Chemistry 0620 Paper 31, May/June 2026

State which substance: is an alkane

State which substance: is made by fermentation

State which substance: is made in a fuel cell

State which substance: has the general formula ${\mathrm{C}}_n{\mathrm{H}}_{2n+2}$

State which substance: is a polymer

State which substance: is used in photosynthesis.

State which two substances are hydrocarbons.

State which two substances are used as solvents.

Use the information in Table 2.1 to answer the following questions. Predict the melting point of iodine.

Use the information in Table 2.1 to answer the following questions. Predict the density of iodine at room temperature and pressure.

Use the information in Table 2.1 to answer the following questions. Deduce the physical state of bromine at $-1{}^{\circ }\mathrm{C}$. Give a reason for your answer. physical state .................................................................................................................... reason ...............................................................................................................................

Use the information in Table 2.1 to answer the following questions. Predict the physical state of fluorine at room temperature and pressure.

Chlorine, bromine and iodine are all non-metals. Aqueous chlorine reacts with aqueous sodium iodide to produce aqueous iodine and aqueous sodium chloride. State the name of this type of reaction.

Chlorine, bromine and iodine are all non-metals. Complete the symbol equation for this reaction. $${\mathrm{C}\mathrm{l}}_2+\text{.....}\mathrm{N}\mathrm{a}\mathrm{I}\to \text{..........}+2\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$$

Chlorine, bromine and iodine are all non-metals. Explain why aqueous bromine does not react with aqueous sodium chloride.

Chlorine, bromine and iodine are all non-metals. On Figure 2.1, complete the dot-and-cross diagram for a molecule of bromine. Show outer shell electrons only.

State the meaning of the symbol (aq) in this equation.

A student investigates the reaction of small pieces of magnesium with excess dilute hydrochloric acid. Figure 3.1 shows the total volume of hydrogen gas released as the reaction proceeds. Name the piece of apparatus used to collect and measure the volume of hydrogen gas produced in this reaction.

Use the graph in Figure 3.1 to determine the total volume of hydrogen gas released in $10\mathrm{s}$. total volume of hydrogen gas = .................................................. ${\mathrm{c}\mathrm{m}}^3$

Use the graph in Figure 3.1 to deduce the time taken for the reaction to finish. time = ....................................................... $\mathrm{s}$

Explain why the reaction finishes.

The student repeats the experiment using the same volume of dilute hydrochloric acid at a higher temperature. Draw a line on the grid in Figure 3.1 to show how the total volume of hydrogen gas released changes over time in this second experiment.

State how the rate of reaction differs, if at all, when larger pieces of magnesium are used.

The student repeats the experiment and adds $1\mathrm{g}$ of a solid, insoluble catalyst. State how the rate of reaction differs, if at all, when a catalyst is added.

The student repeats the experiment and adds $1\mathrm{g}$ of a solid, insoluble catalyst. Describe how the student can show the catalyst is unchanged at the end of the reaction. In your answer, include how the catalyst is separated from the reaction mixture.

Compound M is unsaturated. Figure 4.1 shows the displayed formula of compound M. On Figure 4.1, draw a circle around the carboxylic acid functional group.

Deduce the molecular formula of compound M.

State why compound M is unsaturated.

Outline how petroleum is separated by fractional distillation. In your answer, include: • the property of the fractions which allows them to be separated • a description of how fractional distillation separates the petroleum into fractions.

Two of the fractions obtained from petroleum are bitumen and fuel oil. State one use of each of these fractions. bitumen ............................................................................................................................. fuel oil ................................................................................................................................

Pentane is a member of the alkane homologous series. Pentane reacts in the same way as ethane. Name the two products of the complete combustion of pentane.

Pentane is a member of the alkane homologous series. Pentane reacts in the same way as ethane. Identify the type of reaction that takes place when pentane reacts with chlorine. Draw a circle around your chosen answer. addition neutralisation redox substitution

State two general properties of a solid. 1 ................................................................................................................................................ 2 ................................................................................................................................................

Complete Table 5.1 to show the separation and arrangement of particles in a solid and a gas. Table 5.1

Draw a line from each statement to the correct change of state.

A sealed gas syringe contains $60{\mathrm{c}\mathrm{m}}^3$ of oxygen gas. State how the pressure inside the syringe changes when the plunger of the syringe is pushed in and the temperature remains constant.

State the period number of cobalt in the Periodic Table.

Deduce the number of electrons, neutrons and protons in the cobalt ion shown. $${}_{27}^{59}{\mathrm{C}\mathrm{o}}^{2+}$$ number of electrons .......................................................................................................... number of neutrons ........................................................................................................... number of protons .............................................................................................................

Cobalt is a transition metal that forms coloured compounds. State two other properties of transition metals. 1 ................................................................................................................................................ 2 ................................................................................................................................................

Cobalt reacts with oxygen to form cobalt(III) oxide. Complete the symbol equation for this reaction. $$\text{.....}\mathrm{C}\mathrm{o}+\text{.....}{\mathrm{O}}_2\to 2{\mathrm{C}\mathrm{o}}_2{\mathrm{O}}_3$$

State if cobalt(III) oxide is an acidic oxide or a basic oxide. Give a reason for your answer.

Another compound of cobalt is cobalt(II) chloride. Molten cobalt(II) chloride is electrolysed using inert graphite electrodes. Define the term electrolysis.

Name a metal that is used as an inert electrode.

Name the products formed at each electrode during the electrolysis of molten cobalt(II) chloride, and give the observations at the positive electrode. product at the negative electrode ...................................................................................... product at the positive electrode ....................................................................................... observations at the positive electrode ............................................................................... ...........................................................................................................................................

Cobalt forms a compound with the nitrate ion. The formula of the compound is $\mathrm{C}\mathrm{o}({\mathrm{N}\mathrm{O}}_3{)}_2$. Complete Table 6.1 to calculate the relative formula mass of $\mathrm{C}\mathrm{o}({\mathrm{N}\mathrm{O}}_3{)}_2$. Table 6.1 relative formula mass = .........................................................

State the percentage of clean, dry air that is nitrogen.

Sulfur dioxide is an air pollutant. State one source of sulfur dioxide in the air.

State one adverse effect of sulfur dioxide in the air.

Oxides of nitrogen are also air pollutants. They form acids when they dissolve in water. Choose the pH value that is acidic. Draw a circle around your chosen answer. pH3 pH7 pH10 pH14

Water from natural sources can be polluted with harmful substances. State why sewage and phosphates in river water are harmful. sewage ..................................................................................................................................... ................................................................................................................................................... phosphates ............................................................................................................................... ...................................................................................................................................................

Name the three elements present in an NPK fertiliser.

Explain why fertilisers are used.

Some fertilisers contain chloride ions. Describe the test to identify aqueous chloride ions. test ............................................................................................................................................ ................................................................................................................................................... observations .............................................................................................................................