0620 Chemistry November 2025 Question Paper 21

A sealed balloon contains air. The temperature of the balloon is increased. Which row describes how the pressure in the balloon and the kinetic energy of the particles in air change? pressure kinetic energy of particles

Ammonia gas is reacted with hydrogen chloride gas using the apparatus shown. Solid ammonium chloride is produced. cotton wool soaked in aqueous ammonia cotton wool soaked in aqueous hydrogen chloride long glass tube solid ammonium chloride Which statement explains why the solid ammonium chloride is formed nearer to the hydrogen chloride?

The table shows information about four different particles. particle nucleon number number of protons number of neutrons number of electrons Na W Na+ X O Y O2– Z What are the values of W, X, Y and Z? W X Y Z

Substances with giant covalent structures can be used as lubricants and as cutting tools for hard materials. The diagrams show how the atoms are arranged in two giant covalent substances, P and Q. P Q key strong covalent bond weak attraction Which statement is correct?

Symbols representing four particles are shown. W  20X Y Z The letters are not the chemical symbols. Which particles have the same number of neutrons?

Which statement describes the formation of bonds in lithium bromide?

Which statement explains why solid magnesium is a good conductor of electricity?

The equation for the reaction between dilute ethanoic acid and aqueous lithium hydroxide is shown. CH3COOH + LiOH  CH3COOLi + H2O In an experiment, 20.0 cm3 of 0.050 mol / dm3 aqueous lithium hydroxide is exactly neutralised by 12.5 cm3 of dilute ethanoic acid. Which statement is correct?

The molecular formulae of four compounds are listed. CH4 C2H6 C3H8 C3H6 Which molecular formulae are also the empirical formulae for the compounds?

The equation for the reaction between copper(II) oxide, CuO, and ammonia is given. 3CuO + 2NH3  3Cu + 3H2O + N2 [Mr: CuO, 80; NH3, 17; H2O, 18; N2, 28] [Ar: Cu, 64] Which statements about this reaction are correct? 80.0 g of copper(II) oxide reacts exactly with 17.0 g of ammonia. 4.0 g of copper(II) oxide reacts with excess ammonia to produce 3.2 g of copper. The mass of water produced in this reaction is greater than the mass of nitrogen.

How many atoms are present in 1.00 mol of argon?

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

Which row describes the reactions during the electrolysis of dilute aqueous sodium chloride? anode reaction cathode reaction

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? The energy of the products formed in the neutralisation reaction is greater than the energy of the reactants. The energy of magnesium and carbon dioxide is greater than the energy of magnesium oxide and carbon. In an exothermic reaction, the energy required to break the bonds is greater than the energy released when the new bonds are formed.

The reaction pathway diagram for a reaction is shown. energy progress of reaction Which row identifies the activation energy, Ea, and the enthalpy change, H, for this reaction? Ea H

Hydrogen peroxide solution decomposes very slowly at room temperature to produce oxygen gas. This gas forms a rising foam when liquid detergent is added. Five test-tubes are half-filled with hydrogen peroxide solution. A drop of liquid detergent is added to each one. Different metal oxides are added to four of the test-tubes and the height of the foam formed after one minute is measured. The results are shown. metal oxide height of foam / cm no metal oxide added 0.1 aluminium oxide 0.1 calcium oxide 0.2 copper(II) oxide 2.3 manganese(IV) oxide 5.4 Which conclusion can be drawn from these results?

Which equation represents one of the reactions in the Contact process?

The ionic equation for the redox reaction between acidified manganate(VII) ions and iodide ions is shown. 2MnO4 –(aq) + 16H+(aq) + 10I–(aq)  2Mn2+(aq) + 5I2(aq) + 8H2O(l) Which row shows the changes in oxidation number for manganese and for iodine during this reaction? manganese iodine from to from to

In the Haber process, nitrogen and hydrogen react to form ammonia. N2 + 3H2 2NH3 The forward reaction is exothermic. Which changes in pressure and temperature increase the yield of ammonia? change in pressure change in temperature

Which statement describes a property of ethanoic acid?

A student adds different solid salts to an excess of water. The student stirs the mixtures to determine the solubilities of the salts. The results are shown. W X Y Z What could the four different salts be? W X Y Z

Four metal oxides are listed. Al 2O3 CaO CuO ZnO Which metal oxides are amphoteric?

The ions formed when element X and element Y react together are shown. ● Element X forms X– ions. ● Element Y forms Y2+ ions. Which row identifies the position of X and of Y in the Periodic Table? X Y

Which properties decrease down the group of alkali metals? melting point density reactivity

Some halide ions are displaced from aqueous potassium halides by halogens. In which mixtures are the halide ions displaced? potassium bromide and chlorine potassium bromide and iodine potassium iodide and chlorine potassium chloride and iodine

What is the correct order of reactivity of the following metals, from least reactive to most reactive?

The equation for the reaction between aluminium and iron(III) oxide is shown. 2Al + Fe2O3  Al 2O3 + 2Fe Which statement about this reaction is correct?

Which row identifies methods used to prevent iron from rusting? greasing painting washing with distilled water

Which statement about the extraction of aluminium by electrolysis is correct?

Catalytic converters are used to remove oxides of nitrogen from exhaust gases. The equation represents one of the reactions that occur in a catalytic converter. 2NO + 2CO  N2 + 2CO2 What is a disadvantage of using a catalytic converter to remove oxides of nitrogen?

Some gases are present in clean, dry air, while other gases are only present in polluted air. Which row is correct? a gas present in clean, dry air a gas only present in polluted air

Petroleum is separated by fractional distillation. Which statement about the fractions produced is correct?

Which structure represents a compound in the alcohol homologous series?

Ethane reacts with chlorine. Which row identifies the type of reaction and the formulae of the products formed? reaction products

Which equation represents the formation of poly(propene) from propene? n

Ethene reacts with hydrogen in an addition reaction to form ethane. Which catalyst is used for this reaction?

What is produced by the bacterial oxidation of ethanol?

Which statement about addition polymers or condensation polymers is correct?

The results of flame tests on three metal salts, X, Y and Z, are shown. metal salt flame test colour X yellow Y lilac Z blue-green Which row identifies the cations present in X, Y and Z? X Y Z

Ethanol can be made by fermentation of sugar, using yeast. This produces a mixture of ethanol and water. How is ethanol separated from this mixture?