IGCSE Chemistry 0620 Paper 32, Oct/Nov 2023

is an unsaturated hydrocarbon

leads to the deoxygenation of water in rivers

is a gas which turns damp red litmus paper blue

is the main constituent of natural gas

is a product of photosynthesis

is a compound of a transition element.

Describe two characteristics of a mixture. 1 ................................................................................................................................................. .................................................................................................................................................... 2 ................................................................................................................................................. ....................................................................................................................................................

Fig. 2.1 shows a fractionating column for separating petroleum into different hydrocarbon fractions. On Fig. 2.1, draw an X inside the column to show where the hydrocarbon with the lowest volatility collects.

Name the fraction labelled A in Fig. 2.1.

State the name of the fraction which has hydrocarbons with the longest chain length.

State one use of the fuel oil fraction.

Table 3.1 shows the average concentrations, in $\text{ng}\mathrm{/}1000{\text{cm}}^3$, of air pollutants in four different years. Table 3.1 Name the oxide pollutant that has the highest concentration in 2021.

Name the pollutant that shows a continuous decrease in concentration from 2019 to 2022.

Calculate the average mass, in ng, of particulates in a $250{\text{cm}}^3$ sample of polluted air in 2019. mass = .............................. ng

State one adverse effect of particulates on health.

Particulates are formed by the incomplete combustion of hydrocarbons. State the meaning of the term incomplete combustion.

Oxides of nitrogen contribute to acid rain. Choose from the list the pH value for an acidic solution. Draw a circle around your chosen answer. pH 5 pH 7 pH 9 pH 13

Complete the sentence about removing oxides of nitrogen from car exhausts by choosing two words from the list. agent catalytic compound converter distillation filter oxidising pump The emission of oxides of nitrogen from car exhausts is reduced by using a .............................. .............................. .

Oxides of nitrogen can be formed by the action of bacteria on nitrates. Name the aqueous solution and the metal used in the test for nitrate ions. aqueous solution ................................................................................................................ metal ...................................................................................................................................

Nitrogen dioxide decomposes when heated. Nitric oxide and oxygen are produced. Complete the symbol equation for this reaction. .....NO${}_2$ $\rightleftharpoons$ 2NO + ...........

State the meaning of the symbol $\rightleftharpoons$.

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

Fig. 4.1 shows the physical states of tin. Name the changes of physical states A and B. A ................................................................................................................................................ B ................................................................................................................................................

Describe solid and liquid tin in terms of the separation and motion of the particles. solid tin separation .................................................................................................................................. .................................................................................................................................................... motion ........................................................................................................................................ .................................................................................................................................................... liquid tin separation .................................................................................................................................. .................................................................................................................................................... motion ........................................................................................................................................ ....................................................................................................................................................

A sealed gas syringe contains $80{\text{cm}}^3$ of carbon dioxide gas. State how decreasing the temperature affects the volume of carbon dioxide gas in the gas syringe when the pressure remains constant.

Table 5.1 shows some properties of some Group I metals. Use the information in Table 5.1 to predict: the boiling point of sodium

the atomic volume of rubidium

the observations when lithium reacts with water

the physical state of lithium at ${1300}^{\circ }\text{C}$. Give a reason for your answer. physical state ...................................................................................................................... reason ................................................................................................................................. .............................................................................................................................................

Iron is extracted in a blast furnace by reduction of iron(III) oxide, ${\text{Fe}}_2{\text{O}}_3$, with carbon monoxide. $${\text{Fe}}_2{\text{O}}_3+3\text{CO}\to 2\text{Fe}+3{\text{CO}}_2$$ Explain how this equation shows that iron(III) oxide is reduced.

Choose the phrase which describes the meaning of (III) in iron(III) oxide. Tick (✓) one box. the number of oxygen atoms in iron(III) oxide the oxidation number of iron in iron(III) oxide the number of CO molecules which react with iron(III) oxide the number of electrons in one atom of iron

Calcium carbonate is added to the blast furnace. The calcium carbonate undergoes thermal decomposition. Complete the word equation for the thermal decomposition of calcium carbonate. calcium carbonate $\to$ [ ] + [ ]

Stainless steel is an alloy. Choose the diagram, A, B, C or D, in Fig. 5.1 that best shows the structure of an alloy. diagram .........................................................................................................................

Give one reason for using stainless steel instead of pure iron for cutlery.

Table 5.2 gives the observations when four different metals react with dilute hydrochloric acid. Put the four metals in order of their reactivity. Put the least reactive metal first.

Fig. 6.1 shows the volume of hydrogen gas released as the reaction proceeds. Deduce the volume of hydrogen gas released after 30 seconds. volume of hydrogen = .............................. ${\text{cm}}^3$

The student repeats the experiment using smaller pieces of magnesium. The mass of magnesium used remains the same. The magnesium is still in excess. All other conditions stay the same. Draw a line on the grid in Fig. 6.1 to show the volume of hydrogen gas released when smaller pieces of magnesium are used.

The student repeats the experiment at a higher temperature of 35°C. All other conditions stay the same. Describe how the rate of reaction differs when a temperature of 35°C is used.

The student repeats the experiment using a lower concentration of acid. All other conditions stay the same. Describe how the rate of reaction differs when a lower concentration of acid is used.

Hydrochloric acid reacts with lithium hydroxide. Complete the word equation for this reaction. hydrochloric acid + lithium hydroxide $\to$ [ ] + [ ]

Choose from the list the word that best describes this reaction. Draw a circle around your chosen answer. addition decomposition neutralisation oxidation

State the colour of a solution of thymolphthalein dissolved in aqueous sodium hydroxide.

Fig. 7.1 shows the displayed formula of fumaric acid. On Fig. 7.1, draw a circle around one carboxylic acid functional group.

Deduce the molecular formula of fumaric acid.

Fumaric acid is a colourless compound. Describe the colour change when excess fumaric acid is added to aqueous bromine. from ............................................................. to .............................................................

Fumaric acid can be oxidised to produce a compound with the molecular formula ${\text{C}}_4{\text{H}}_6{\text{O}}_6$. Complete Table 7.1 to calculate the relative molecular mass of ${\text{C}}_4{\text{H}}_6{\text{O}}_6$. Table 7.1 relative molecular mass = ..............................

Ethanoic acid is a carboxylic acid. Complete the word equation for the reaction of ethanoic acid with sodium carbonate. ethanoic acid + sodium carbonate $\to$ [ ] + [ ] + [ ]

Ethanoic acid can be produced by the oxidation of ethanol. State one use of ethanol.

Ethanol, ${\text{C}}_2{\text{H}}_5\text{OH}$, is an alcohol. Choose from the list the general formula for the alcohol homologous series. Draw a circle around your chosen answer. ${\text{C}}_n{\text{H}}_n\text{OH}{\text{C}}_n{\text{H}}_{2n+1}\text{OH}{\text{C}}_n{\text{H}}_{2n+2}\text{OH}{\text{C}}_{2n}{\text{H}}_{2n}\text{OH}$

Ethanol can be manufactured by the addition of steam to ethene. State two conditions for this reaction. 1 .......................................................................................................................................... 2 ..........................................................................................................................................

Ionic compounds are good electrical conductors when molten or in aqueous solution. Describe one other physical property of ionic compounds.

Complete Fig. 8.1 to show: ● the electronic configuration of a chloride ion ● the charge on the ion.

Deduce the number of protons and neutrons in the zinc ion shown. ${}_{30}^{67}{\text{Zn}}^{2+}$ number of protons .............................................................................................................. number of neutrons ............................................................................................................

Complete this sentence about positive ions. Positive ions are known as ......................................................................................... .

Molten zinc chloride is electrolysed using graphite electrodes. State the names of the products at each electrode and give the observations at the positive electrode. product at the negative electrode .............................................................................................. product at the positive electrode ................................................................................................ observations at the positive electrode ....................................................................................................................................................

Graphite electrodes conduct electricity. State one other property that the electrode should have.

Choose the correct statement about the structure and bonding in graphite. Tick (✓) one box. simple ionic simple covalent giant ionic giant covalent

State one use of graphite other than as an electrode.