Cambridge A Level Chemistry 9701 — 2020 May/June Paper 1 · Variant 1

Question 1

1 Ethene can be oxidised to form epoxyethane, C2H4O. C2H4(g)  +  2 1O2(g) C2H4O(g) ∆H o = –107 kJ mol–1 Which set of conditions gives the greatest yield of epoxyethane at equilibrium? temperature pressure / °C A high 100 B high 200 C low 100 D low 200

Accepted Answer

A

Question 2

2 Cobalt can form the positive ion Co(NH3)4Cl 2 +. What is the oxidation number of cobalt in this ion? A +1 B +2 C +3 D +6

Accepted Answer

C

Question 3

3 When considering one molecule of ethene, which row describes both the hybridisation of the atomic orbitals in the carbon atoms and the overall bonding? hybridisation bonding A sp2 4 σ bonds 1 π bond B sp2 5 σ bonds 1 π bond C sp3 4 σ bonds 1 π bond D sp3 5 σ bonds 1 π bond

Accepted Answer

B

Question 4

4 10 cm3 of ethane is burned in 45 cm3 of oxygen at a pressure of 101 kPa and a temperature of 200 °C. Complete combustion takes place. What is the total volume of gas present when the reaction is complete, measured under the same conditions? A 30 cm3 B 50 cm3 C 55 cm3 D 60 cm3

Accepted Answer

D

Question 5

5 Two reactions are shown. H2(g)  →  2H(g) CO(g)  +  2 1O2(g)  →  CO2(g) If molar amounts are used, how can the two energy changes associated with these reactions be described? A enthalpy of atomisation and enthalpy of combustion B enthalpy of atomisation and enthalpy of formation C bond energy and enthalpy of combustion D bond energy and enthalpy of formation

Accepted Answer

C

Question 6

6 The diagram shows the Boltzmann energy distribution curves for molecules of a sample of a gas at two different temperatures. Which letter on the axes represents the most probable energy for molecules of the same sample of gas at the lower temperature? A B C D

Accepted Answer

C

Question 7

7 What are the units of Kp for the reaction shown? H2O(g)  +  C(s) H2(g)  +  CO(g) A Pa–1 B Pa C Pa2 D no units

Accepted Answer

B

Question 8

8 In this question you should use changes in oxidation numbers to balance a chemical equation. Acidified potassium dichromate(VI) solution can oxidise a solution of V2+ ions. The equation for this reaction is shown. a Cr2O7 2–  +  b V2+  +  c H+  →  d Cr3+  +  e VO3 –  +  f H2O What is the ratio a : b in the correctly balanced equation? A 1 : 1 B 1 : 2 C 2 : 1 D 4 : 1

Accepted Answer

B

Question 9

9 A sample of argon gas has a mass of 0.20 g, at a pressure of 100 000 Pa and a temperature of 12 °C. Which volume does the gas occupy? A 1.2 × 10–4 cm3 B 5.0 cm3 C 59 cm3 D 119 cm3

Accepted Answer

D

Question 10

10 In which pair does each species have the same number of unpaired electrons? A Al and Cu2+ B Ca and Cr3+ C Ca and Ni2+ D Fe3+ and O2–

Accepted Answer

A

Question 11

11 A sample of solid ammonium chloride decomposes on heating. solid ammonium chloride  →  ammonia gas  +  hydrogen chloride gas A total of 2.4 × 1021 molecules of gas is formed. How many hydrogen atoms are present in the gaseous products? A 1.2 × 1021 B 2.4 × 1021 C 4.8 × 1021 D 9.6 × 1021

Accepted Answer

C

Question 12

12 A white powder is a mixture of sodium chloride and sodium iodide. It is dissolved in water in a test-tube. An excess of aqueous silver nitrate is added to the test-tube. A precipitate, X, is observed. An excess of concentrated ammonia is then added to the test-tube containing X. After the test-tube has been shaken, a precipitate, Y, is observed. Which statement about X or Y is correct? A X is a pure white colour. B X is pure silver iodide. C Y is pure silver chloride. D Y is yellow.

Accepted Answer

D

Question 13

13 6.90 g of an ammonium salt is heated with an excess of aqueous sodium hydroxide. The volume of ammonia produced, measured under room conditions, is 2.51 dm3. Which ammonium salt is used? A ammonium carbonate (Mr = 96.0) B ammonium chloride (Mr = 53.5) C ammonium nitrate (Mr = 80.0) D ammonium sulfate (Mr = 132.1)

Accepted Answer

D

Question 14

14 An excess of MgO is shaken with water. The resulting mixture is filtered into test-tube P. An excess of BaO is shaken with water. The resulting mixture is filtered into test-tube Q. Which oxide reacts more readily with water and which filtrate has the lower pH? oxide reacts more test-tube with readily with water filtrate of lower pH A BaO P B BaO Q C MgO P D MgO Q

Accepted Answer

A

Question 15

15 Element Z has a giant structure. The chloride of Z reacts with water to give a solution with a pH less than 5. Which pair shows two elements which could be Z? A aluminium, magnesium B aluminium, silicon C phosphorus, magnesium D phosphorus, silicon

Accepted Answer

B

Question 16

16 Sodium, aluminium and silicon are three elements in Period 3. Each element forms an oxide. Which row has three correct properties of these oxides? sodium oxide aluminium oxide silicon dioxide A basic basic amphoteric B giant ionic giant ionic simple molecular C high melting point low melting point high melting point D reacts with water no reaction with water no reaction with water

Accepted Answer

D

Question 17

17 0.25 g of anhydrous magnesium nitrate is heated strongly until it completely decomposes. What is the total volume of gas produced, measured under room conditions? A 40 cm3 B 81 cm3 C 101 cm3 D 202 cm3

Accepted Answer

C

Question 18

18 Astatine, At, is below iodine in Group 17 of the Periodic Table. Which statement is most likely to be correct? A AgAt(s) reacts with an excess of dilute aqueous ammonia to form a solution of a soluble complex. B Astatine and KCl (aq) react to form KAt(aq) and chlorine. C KAt(aq) and dilute sulfuric acid react to form HAt(g). D NaAt(s) and concentrated sulfuric acid react to form astatine.

Accepted Answer

D

Question 19

19 What is the order of increasing melting point of the three chlorides shown? CCl 4          MgCl 2          PCl 5 lowest highest melting point melting point A CCl 4 PCl 5 MgCl 2 B MgCl 2 CCl 4 PCl 5 C MgCl 2 PCl 5 CCl 4 D PCl 5 CCl 4 MgCl 2

Accepted Answer

A

Question 20

20 The skeletal formula of compound X is shown. O Which row is correct? observation on molecular addition of X to formula of X Fehling’s reagent A C7H14O no change B C7H14O red precipitate forms C C7H16O no change D C7H16O red precipitate forms

Accepted Answer

A

Question 21

21 Which statement is correct? A 2,2-dimethylpropanoic acid is an isomer of propyl methanoate. B 2-methylbutan-2-ol is an isomer of hexan-3-ol. C 3-methylbutan-2-one is an isomer of pentanal. D 3,3-dimethylbutan-2-one is an isomer of pentan-3-one.

Accepted Answer

C

Question 22

22 But-1-ene and but-2-ene are treated separately with cold, dilute acidified manganate(VII) ions. Four students, W, X, Y and Z, make statements about these alkenes and the diols formed from them. W One diol contains two primary alcohol groups. X One diol contains a primary and a secondary alcohol group. Y One diol contains two secondary alcohol groups. Z Both alkenes exhibit cis-trans isomerism. Which two students are correct? A W and Y B W and Z C X and Y D X and Z

Accepted Answer

C

Question 23

23 2-bromo-2-methylpentane is a tertiary halogenoalkane. Which organic products are formed when 2-bromo-2-methylpentane reacts with a hot concentrated ethanolic solution of sodium hydroxide? A 2-methylpent-1-ene only B 2-methylpent-1-ene and 2-methylpent-2-ene C 2-methylpent-2-ene only D 2-methylpent-2-ene and 4-methylpent-2-ene

Accepted Answer

B

Question 24

24 Poly(propene) is an addition polymer. What are the C–C–C bond angles along its polymer chain? A They are all 109°. B Half of them are 109° and half are 120°. C Half of them are 90° and half are 180°. D They are all 120°.

Accepted Answer

A

Question 25

25 An alcohol has the molecular formula C5H12O. It has several isomers. Which isomer forms a yellow precipitate with alkaline aqueous iodine? A 2,2-dimethylpropan-1-ol B 2-methylbutan-2-ol C 3-methylbutan-2-ol D pentan-3-ol

Accepted Answer

C

Question 26

26 When compound X is heated under reflux with aqueous sodium hydroxide solution two products are formed: sodium ethanoate and hexan-1-ol. What is compound X? A B C D O O O O O O O O

Accepted Answer

D

Question 27

27 What is the major product Z of the following reaction? an excess of dry HBr Z warm A B C D Br Br Br Br Br Br Br Br

Accepted Answer

B

Question 28

28 The structure of compound Q is shown. compound Q O O O O How many chiral centres are present in a molecule of Q? A 4 B 5 C 6 D 7

Accepted Answer

D

Question 29

29 Compound X has the infra-red spectrum shown. 100 transmittance / % 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 What could be the identity of compound X? A ethanoic acid B ethanol C ethylethanoate D propanone

Accepted Answer

A

Question 30

30 Which reaction produces an organic anion with a good yield? A heating ethanenitrile under reflux with dilute sodium hydroxide B heating ethanenitrile under reflux with dilute sulfuric acid C heating ethane with sodium metal D heating ethanol under reflux with dilute sodium hydroxide Section B

Accepted Answer

A

Question 31

31 The definitions of many chemical terms can be illustrated by chemical equations. Which terms can be illustrated by an equation that includes the formation of a positive ion? 1 first ionisation energy 2 heterolytic fission of a covalent bond 3 enthalpy change of atomisation

Accepted Answer

B

Question 32

32 Which molecules have no overall dipole moment? 1 boron trifluoride 2 methane 3 phosphorus pentafluoride

Accepted Answer

A

Question 33

33 Carbon exists in several different forms. Two of these forms are buckminsterfullerene and graphene. Buckminsterfullerene is a fullerene allotrope of carbon. Which statements about buckminsterfullerene and graphene are correct? 1 Both have delocalised electrons. 2 Buckminsterfullerene has a giant molecular structure. 3 The carbon atoms in graphene form a tetrahedral lattice.

Accepted Answer

D

Question 34

34 Carbon monoxide burns readily in oxygen to form carbon dioxide. What does this information suggest? 1 The +4 oxidation state of carbon is more stable than the +2 state. 2 The standard enthalpy change of formation of carbon dioxide is more negative than the standard enthalpy change of formation of carbon monoxide. 3 The value of the equilibrium constant for the reaction, 2CO(g)  +  O2(g) 2CO2(g), is likely to be high.

Accepted Answer

A

Question 35

35 The catalytic converters fitted to cars remove pollutants from the exhaust gases. Some of the reactions that occur involve oxygen, which comes from the air. Which pollutants in the exhaust gases will react with oxygen on the surface of the catalytic converter? 1 NO2 2 unburnt fuel 3 CO

Accepted Answer

C

Question 36

36 Chlorine reacts with sodium hydroxide in two different ways depending upon the temperature. reaction 1 Cl 2  +  2OH–  →  Cl –  +  Cl O–  +  H2O reaction 2 3Cl 2  +  6OH–  →  5Cl –  +  Cl O3 –  +  3H2O Which statements about these reactions are correct? 1 Reaction 2 requires a higher temperature than reaction 1. 2 The products of reaction 1 show chlorine in two different oxidation states. 3 The products of reaction 2 show oxygen in two different oxidation states.

Accepted Answer

B

Question 37

37 In which of the reactions is the organic compound oxidised by the given reagent? 1 CH3CHO  +  HCN reagent 2 CH3CH2CH2CHO  +  Tollens’ reagent 3 CH3CH2CHO  +  Fehling’s reagent

Accepted Answer

C

Question 38

38 When the apparatus is set up as shown, an orange precipitate forms in test-tube Z. Y Z air compound Q + acidified potassium 2,4-dinitrophenylhydrazine dichromate(VI) reagent warm What could compound Q be? 1 CH3CH2CH2OH 2 CH3CH(OH)CH3 3 (CH3)3COH

Accepted Answer

B

Question 39

39 Chlorofluoroalkanes that diffuse into the stratosphere are broken down by ultraviolet radiation. Radicals are generated that cause depletion of ozone. What are these radicals? 1 chlorine radicals 2 fluorine radicals 3 alkyl radicals

Accepted Answer

D

Question 40

40 A mixture of the three isomers of C2H2Cl 2 is polymerised. Which sequences will be seen within the polymer chains? 1 2 3 Cl H H H Cl H C C C C C C Cl Cl Cl Cl H H

Accepted Answer

A

Question paper16 pages

Mark scheme3 pages

Questions as text

Q1 · Ethene can be oxidised to form epoxyethane, C2H4O

Q2 · Cobalt can form the positive ion Co(NH3)4Cl 2 +

Q3 · When considering one molecule of ethene, which row describes both the hybridisation of…

Q4 · 10 cm3 of ethane is burned in 45 cm3 of oxygen at a pressure of 101 kPa and a temperature…

Q5 · Two reactions are shown

Q6 · The diagram shows the Boltzmann energy distribution curves for molecules of a sample of a…

Q7 · What are the units of Kp for the reaction shown?

Q8 · In this question you should use changes in oxidation numbers to balance a chemical…

Q9 · A sample of argon gas has a mass of 0.20 g, at a pressure of 100 000 Pa and a temperature…

Q10 · In which pair does each species have the same number of unpaired electrons?

Q11 · A sample of solid ammonium chloride decomposes on heating

Q12 · A white powder is a mixture of sodium chloride and sodium iodide

Q13 · 6.90 g of an ammonium salt is heated with an excess of aqueous sodium hydroxide

Q14 · An excess of MgO is shaken with water

Q15 · Element Z has a giant structure

Q16 · Sodium, aluminium and silicon are three elements in Period 3

Q17 · 0.25 g of anhydrous magnesium nitrate is heated strongly until it completely decomposes

Q18 · Astatine, At, is below iodine in Group 17 of the Periodic Table

Q19 · What is the order of increasing melting point of the three chlorides shown?

Q20 · The skeletal formula of compound X is shown

Q21 · Which statement is correct?

Q22 · But-1-ene and but-2-ene are treated separately with cold, dilute acidified manganate(VII)…

Q23 · 2-bromo-2-methylpentane is a tertiary halogenoalkane

Q24 · Poly(propene) is an addition polymer

Q25 · An alcohol has the molecular formula C5H12O

Q26 · When compound X is heated under reflux with aqueous sodium hydroxide solution two…

Q27 · What is the major product Z of the following reaction?

Q28 · The structure of compound Q is shown

Q29 · Compound X has the infra-red spectrum shown

Q30 · Which reaction produces an organic anion with a good yield?

Q31 · The definitions of many chemical terms can be illustrated by chemical equations

Q32 · Which molecules have no overall dipole moment?

Q33 · Carbon exists in several different forms

Q34 · Carbon monoxide burns readily in oxygen to form carbon dioxide

Q35 · The catalytic converters fitted to cars remove pollutants from the exhaust gases

Q36 · Chlorine reacts with sodium hydroxide in two different ways depending upon the temperature

Q37 · In which of the reactions is the organic compound oxidised by the given reagent?

Q38 · When the apparatus is set up as shown, an orange precipitate forms in test-tube Z

Q39 · Chlorofluoroalkanes that diffuse into the stratosphere are broken down by ultraviolet…

Q40 · A mixture of the three isomers of C2H2Cl 2 is polymerised

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