Cambridge A Level Chemistry 9701 — 2021 May/June Paper 1 · Variant 1

Question 1

1 Which contains the largest number of hydrogen atoms? A 0.10 mol of pentane B 0.20 mol of but-2-ene C 1.00 mol of hydrogen molecules D 6.02  1023 hydrogen atoms

Accepted Answer

C

Question 2

2 In which pair of species do both species have only one unpaired p electron? A Ar+ and C– B B and Ti+ C F and Ga D Se– and Si–

Accepted Answer

C

Question 3

3 Phosphorus forms two chlorides. Phosphorus(III) chloride, PCl 3, is a covalent liquid. Phosphorus(V) chloride is an ionic solid. One of the ions present is [PCl 4]+. What is the shape of the PCl 3 molecule and the [PCl 4]+ ion? PCl 3 [PCl 4]+ A pyramidal square planar B pyramidal tetrahedral C tetrahedral square planar D trigonal planar tetrahedral

Accepted Answer

B

Question 4

4 is the standard enthalpy of formation of methane. is the standard enthalpy of combustion of carbon. is the standard enthalpy of combustion of hydrogen. CH4(g)  +  2O2(g) CO2(g)  +  2H2O(l) Which expression is equivalent to         ? A – + B – 2 – C – + D + 2 –

Accepted Answer

D

Question 5

5 The diagram shows the Boltzmann distribution for the same gas at two different temperatures, T1 and T2. T1 T2 y 0 0 x What is plotted on the y-axis and which line represents the higher temperature? plotted on y-axis higher temperature A number of molecules T1 B number of molecules T2 C molecular energy T1 D molecular energy T2

Accepted Answer

B

Question 6

6 What is the minimum mass of oxygen required to ensure the complete combustion of 12 dm3 of propane measured under room conditions? A 60 g B 80 g C 120 g D 160 g

Accepted Answer

B

Question 7

7 Why is the first ionisation energy of oxygen less than that of nitrogen? A The nitrogen atom has its outer electron in a different subshell. B The nuclear charge on the oxygen atom is greater than that on the nitrogen atom. C The oxygen atom has a pair of electrons in one p orbital that repel one another. D There is more shielding in an oxygen atom.

Accepted Answer

C

Question 8

8 Which gas would behave most like an ideal gas under room conditions? A helium B nitrogen C ammonia D krypton

Accepted Answer

A

Question 9

9 When hydrogen iodide is reacted with concentrated sulfuric acid, several reactions occur, including: 8HI  +  H2SO4    H2S  +  4H2O  +  4I2 Which row gives the change in oxidation number of iodine and of sulfur in this reaction? change in oxidation change in oxidation number of iodine number of sulfur A –1 +6 B –1 +8 C +1 –6 D +1 –8

Accepted Answer

D

Question 10

10 The diagram represents the Haber process for the manufacture of ammonia from nitrogen and hydrogen. heat exchanger N2 + H2 catalytic converter condenser NH3 What is the purpose of the heat exchanger? A to cool the incoming gas mixture to avoid overheating the catalyst B to cool the reaction products and separate the NH3 from unused N2 and H2 C to warm the incoming gas mixture and shift the equilibrium to give more NH3 D to warm the incoming gas mixture and speed up the reaction

Accepted Answer

D

Question 11

11 Which statement about catalysts is correct? A They change the reaction pathway by increasing the activation energy. B They increase the rate of reaction by lowering the enthalpy change of the reaction. C They increase the number of particles that have sufficient energy to react. D Heterogeneous catalysts are in the same state as the reactant.

Accepted Answer

C

Question 12

12 Element X is in Period 3. Element X forms a solid oxide Y. Y reacts with hot concentrated hydrochloric acid. Y reacts with hot aqueous sodium hydroxide to form a compound in which X is part of an anion. How many p electrons does one atom of X have in its outer shell? A 0 B 1 C 2 D 3

Accepted Answer

B

Question 13

13 The gaseous products of heating a mixture of Ca(OH)2 and NH4Cl are passed through solid CaO. A single gaseous product, W, is collected. A sample of W reacts with Cl 2(g) to produce two gases, X and Y. X is an element. Y is acidic. Y reacts with W to produce Z. What are X and Z? X Z A N2 CaCl 2 B N2 NH4Cl C O2 CaCl 2 D O2 NH4Cl

Accepted Answer

B

Question 14

14 Q is a mixture of a Group 2 oxide and a Group 2 sulfate. Q contains equal amounts of the two compounds. Q is shaken with water and the resulting mixture filtered; a solid residue is obtained. There is no reaction when the solid residue is shaken with HCl (aq). Shaking the filtrate with H2SO4(aq) produces a white precipitate. What could be Q? A BaO + BaSO4 B BaO + MgSO4 C MgO + BaSO4 D MgO + MgSO4

Accepted Answer

A

Question 15

15 Which substance will not be a product of the thermal decomposition of hydrated magnesium nitrate? A dinitrogen monoxide B magnesium oxide C oxygen D steam

Accepted Answer

A

Question 16

16 A 5 cm3 sample of 0.05 mol dm–3 sodium chloride is mixed with a 5 cm3 sample of 0.05 mol dm–3 potassium iodide. 10 cm3 of acidified 0.05 mol dm–3 silver nitrate is then added, followed by concentrated ammonia solution. What is seen after the addition of an excess of concentrated ammonia solution? A a cream precipitate B a white precipitate C a yellow precipitate D no precipitate

Accepted Answer

C

Question 17

17 The volatility of the Group 17 elements, chlorine, bromine and iodine, decreases down the group. What is responsible for this trend? A bond length in the halogen molecule B bond strength in the halogen molecule C electronegativity of the halogen atom D number of electrons in the halogen atom

Accepted Answer

D

Question 18

18 Acid rain is a dilute solution of sulfuric acid. Which pollutant also contributes to the formation of acid rain? A carbon monoxide B carbon dioxide C nitrogen dioxide D hydrocarbons

Accepted Answer

C

Question 19

19 R is an oxide of Period 3 element T. 5.00 g of R contains 2.50 g of T. What is T? A magnesium B aluminium C silicon D sulfur

Accepted Answer

D

Question 20

20 Bromoethane reacts with cyanide ions, producing propanenitrile. Which statement about the SN2 mechanism of this reaction is correct? A The lone pair of electrons on C of CN– attacks the carbon atom of the C–Br bond. B The lone pair of electrons on C of CN– attacks the carbocation formed when the C–Br bond breaks. C The lone pair of electrons on N of CN– attacks the carbon atom of the C–Br bond. D The lone pair of electrons on N of CN– attacks the carbocation formed when the C–Br bond breaks.

Accepted Answer

A

Question 21

21 Which compound would produce two different carboxylic acids when treated with hot, concentrated, acidified manganate(VII) ions? A B C D

Accepted Answer

B

Question 22

22 Which compound could show both cis-trans isomerism and optical isomerism? A B C D Cl Cl O Br Cl H H H Br Br Br C Br C C C Br C C C Br C C Br C C Cl C C I Br H I H Cl H Br H

Accepted Answer

B

Question 23

23 Limonene is a hydrocarbon found in the rind of citrus fruits. limonene What is the molecular formula of limonene? A C10H12 B C10H14 C C10H16 D C10H18

Accepted Answer

C

Question 24

24 The compound cetyl palmitate, C15H31CO2C16H33, is a waxy solid. Cetyl palmitate is heated under reflux with an excess of aqueous sodium hydroxide. Which products will be formed? A C15H31ONa  and  C16H33CO2Na B C15H31CO2Na  and  C16H33ONa C C15H31OH  and  C16H33CO2Na D C15H31CO2Na  and  C16H33OH

Accepted Answer

D

Question 25

25 When an organic compound is oxidised, any oxygen atom gained by the organic molecule is considered to be from a water molecule also producing  2H+  +  2e–. Any hydrogen atom lost may be considered to be lost as  H+  +  e–. These changes can be represented by the following two equations. H2O    [O]  +  2H+  +  2e– [H]    H+  +  e– Compound X is oxidised by heating under reflux with hot, acidified potassium dichromate(VI) for one hour. The half-equation for the reduction reaction is shown. Cr2O7 2–  +  14H+  +  6e–    2Cr3+  +  7H2O Under these conditions, one mole of potassium dichromate(VI) oxidises three moles of X. What could X be? A propanal B propan-1-ol C propan-1,2-diol D propan-1,3-diol

Accepted Answer

A

Question 26

26 Compound X has the empirical formula C2H4O. Its infra-red spectrum is shown. 100 transmittance / % 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 What could be the skeletal formula of compound X? A B C D OH O O O O O O H OH

Accepted Answer

A

Question 27

27 How many moles of hydrogen, H2, are evolved when an excess of sodium metal is added to one mole of citric acid? citric acid CO2H HO C CH2CO2H CH2CO2H A 0.5 B 1.5 C 2 D 4

Accepted Answer

C

Question 28

28 Which statement is correct for the reaction of carbonyl compounds with HCN? A The reaction is catalysed by concentrated H2SO4. B Pentan-2-one and HCN react to give a chiral product. C The reaction is a condensation reaction. D The reaction is nucleophilic substitution.

Accepted Answer

B

Question 29

29 The table describes four reactions of propene. Which row is correct? name of main reagent used organic product A aqueous bromine 2-bromopropane B cold acidified aqueous potassium manganate(VII) propane-1,3-diol C hydrogen chloride 2-chloropropane D steam propan-1-ol

Accepted Answer

C

Question 30

30 Butanoic acid is prepared from 1-bromopropane. This synthesis requires a sequence of two reactions. Which compound is prepared in the first stage of the synthesis? A 1-aminopropane B propan-1-ol C butanal D butanenitrile

Accepted Answer

D

Question 31

31 Ethanol combines with ethanoic acid to form ethyl ethanoate according to the following reaction. C2H5OH(I)  +  CH3CO2H(I) CH3CO2C2H5(I)  +  H2O(I) ∆H o = –6 kJ mol–1 9.2 g ethanol, 12 g ethanoic acid and 8.8 g ethyl ethanoate are mixed and allowed to stand at 298 K, until equilibrium is reached. (Mr:  C2H5OH, 46;  CH3CO2H, 60;  CH3CO2C2H5, 88) The resulting equilibrium mixture is found to contain 4.8 g ethanoic acid. The experiment is repeated at 323 K. Which statements are correct? 1 There are 0.22 moles of ethyl ethanoate in the mixture at equilibrium at 298 K. 2 The equilibrium mixture at 323 K will contain more than 4.8 g of ethanoic acid. 3 If a small amount of water is added at the start of either experiment the value of Kc would not be affected.

Accepted Answer

A

Question 32

32 The diagram shows an incomplete energy profile diagram for a reaction. products enthalpy reactants progress of reaction Which reactions could this diagram refer to? 1 CaCO3(s)    CaO(s)  +  CO2(g) 2 H2(g)    2H(g) 3 Cl –(aq)    Cl –(g)  +  aq

Accepted Answer

A

Question 33

33 A gaseous hydrocarbon has a density of 2.42 g dm–3 under room conditions. What could be the skeletal formula of this hydrocarbon? 1 2 3

Accepted Answer

D

Question 34

34 Which molecules contain at least one bond angle of 120? 1 C2H4 2 PF5 3 NCl 3

Accepted Answer

B

Question 35

35 Which statements are correct going across Period 3 from sodium to chlorine? 1 The charge on the nucleus increases, pulling the electrons closer to it. 2 The radius of the most common ion of each element decreases. 3 The shielding caused by inner electrons decreases, so the outer electrons are pulled closer to the nucleus.

Accepted Answer

D

Question 36

36 Which statements are correct? 1 Magnesium carbonate decomposes at a lower temperature than calcium carbonate. 2 Calcium hydroxide is more soluble in water than magnesium hydroxide. 3 Calcium is a stronger reducing agent than magnesium.

Accepted Answer

A

Question 37

37 Which statements are correct? 1 1,1-difluoroethane is less reactive than 1,1-dichloroethane. 2 1,1-difluoroethane is polar. 3 The C–F bond is stronger than the C–Cl bond.

Accepted Answer

A

Question 38

38 Which pairs of compounds may be distinguished by testing with alkaline aqueous iodine? 1 butanal and butanone 2 pentan-2-one and pentan-3-ol 3 propanone and propan-2-ol

Accepted Answer

B

Question 39

39 Which reactions have a coloured organic product? 1 ethanal  +  2,4-dinitrophenylhydrazine reagent 2 ethanol  +  acidified potassium dichromate(VI) 3 ethene  +  cold dilute acidified potassium manganate(VII)

Accepted Answer

D

Question 40

40 Propanoic acid is reacted with an excess of lithium aluminium hydride. The organic product of this reaction is reacted with ethanoic acid in the presence of concentrated sulfuric acid, forming product X. What are major commercial uses of X? 1 fuel 2 solvent 3 flavouring

Accepted Answer

C

Question paper16 pages

Mark scheme3 pages

Questions as text

Q1 · Which contains the largest number of hydrogen atoms?

Q2 · In which pair of species do both species have only one unpaired p electron?

Q3 · Phosphorus forms two chlorides

Q4 · Is the standard enthalpy of formation of methane

Q5 · The diagram shows the Boltzmann distribution for the same gas at two different…

Q6 · What is the minimum mass of oxygen required to ensure the complete combustion of 12 dm3…

Q7 · Why is the first ionisation energy of oxygen less than that of nitrogen?

Q8 · Which gas would behave most like an ideal gas under room conditions?

Q9 · When hydrogen iodide is reacted with concentrated sulfuric acid, several reactions occur…

Q10 · The diagram represents the Haber process for the manufacture of ammonia from nitrogen and…

Q11 · Which statement about catalysts is correct?

Q12 · Element X is in Period 3

Q13 · The gaseous products of heating a mixture of Ca(OH)2 and NH4Cl are passed through solid…

Q14 · Q is a mixture of a Group 2 oxide and a Group 2 sulfate

Q15 · Which substance will not be a product of the thermal decomposition of hydrated magnesium…

Q16 · A 5 cm3 sample of 0.05 mol dm–3 sodium chloride is mixed with a 5 cm3 sample of 0.05 mol…

Q17 · The volatility of the Group 17 elements, chlorine, bromine and iodine, decreases down the…

Q18 · Acid rain is a dilute solution of sulfuric acid

Q19 · R is an oxide of Period 3 element T

Q20 · Bromoethane reacts with cyanide ions, producing propanenitrile

Q21 · Which compound would produce two different carboxylic acids when treated with hot…

Q22 · Which compound could show both cis-trans isomerism and optical isomerism?

Q23 · Limonene is a hydrocarbon found in the rind of citrus fruits

Q24 · The compound cetyl palmitate, C15H31CO2C16H33, is a waxy solid

Q25 · When an organic compound is oxidised, any oxygen atom gained by the organic molecule is…

Q26 · Compound X has the empirical formula C2H4O

Q27 · How many moles of hydrogen, H2, are evolved when an excess of sodium metal is added to…

Q28 · Which statement is correct for the reaction of carbonyl compounds with HCN?

Q29 · The table describes four reactions of propene

Q30 · Butanoic acid is prepared from 1-bromopropane

Q31 · Ethanol combines with ethanoic acid to form ethyl ethanoate according to the following…

Q32 · The diagram shows an incomplete energy profile diagram for a reaction

Q33 · A gaseous hydrocarbon has a density of 2.42 g dm–3 under room conditions

Q34 · Which molecules contain at least one bond angle of 120?

Q35 · Which statements are correct going across Period 3 from sodium to chlorine?

Q36 · Which statements are correct?

Q37 · Which statements are correct?

Q38 · Which pairs of compounds may be distinguished by testing with alkaline aqueous iodine?

Q39 · Which reactions have a coloured organic product?

Q40 · Propanoic acid is reacted with an excess of lithium aluminium hydride

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