Chemistry 2020 May/June | Past Paper

Q1

MCQ 1 mark

In which carbon allotrope are all electrons localised? A buckminsterfullerene B diamond C graphite D graphene

A

buckminsterfullerene

B

diamond

C

graphite

D

graphene

Q2

MCQ 1 mark

A copper ore contains 3.00% of copper carbonate, CuCO3, by mass. Which mass of copper would be obtained from 1 tonne of the ore? A 1.91 kg B 3.71 kg C 15.4 kg D 58.4 kg

A

copper ore contains 3.00% of copper carbonate, CuCO3, by mass.

A

1.91

Q3

Short Answer 1 mark

The catalysed formation of ammonia by the Haber process can be represented by the equation shown. 2

Q3(g)

Short Answer 1 mark

+ 3H2

Q3(g)

Short Answer 1 mark

Which change in conditions will increase both the rate of formation and the equilibrium yield of ammonia? A decrease in the temperature B increase in the temperature C increase in the pressure D increase in the surface area of the catalyst

Q4

Short Answer 1 mark

Solid sulfur consists of S 8 molecules. Which equation represents the standard enthalpy of atomisation of sulfur?C SD S

Q5

Short Answer 1 mark

In this question you should use changes in oxidation numbers to balance a chemical equation. The following reaction occurs when MnO 2 is warmed with dilute H2SO4. a MnO 2 + b H + d MnO 4 - + e H 2O What is the ratio of c : d in the correctly balanced equation? A 1 : 1 B 1 : 2 C 2 : 3 D 3 : 2

Q6

MCQ 1 mark

In this question you should assume air contains 21% oxygen. What is the minimum volume of air required to ensure complete combustion of 10 of butane gas, under room conditions? A 14 B 27 cm C 65 cm D 310 cm

A

14

B

27 cm

C

65 cm

D

310 cm

Q7

MCQ 1 mark

When aqueous bromine is shaken with cyclohexane and allowed to stand, two layers form. The top cyclohexane layer is coloured and the bottom aqueous layer is almost colourless. What is the most likely explanation for this observation? A Bromine is reduced to bromide ions in the bottom layer. B Bromine molecules are non-polar. C Bromine reacts with water but cannot react with cyclohexane. D The product of the reaction between bromine and cyclohexane is coloured.

A

Bromine is reduced to bromide ions in the bottom layer.

B

Bromine molecules are non-polar.

C

Bromine reacts with water but cannot react with cyclohexane.

D

The product of the reaction between bromine and cyclohexane is coloured.

Q8

Short Answer 1 mark

In which change are only temporary dipole-induced dipole forces overcome?A CB HC OD C

Q9

Short Answer 1 mark

The complete combustion of 2 moles of an alkane produces 400 of carbon dioxide measured at 301 K and 1 × 10 Pa. Carbon dioxide can be assumed to behave as an ideal gas under these conditions. What is the formula of the alkane?A C 8H18 B C 16H34 C C 20H42 D C 40H82

Q10

MCQ 1 mark

In which reaction does an element undergo the largest change in oxidation number? A Cl 2 + 2OH + Cl + H2O B 3Cl 2 + 6OH - + 5Cl + 3H2O C Cr2O7 2- + 6Fe + 14H + 6Fe + 7H2O D 3MnO 2- + 4H - + 2H2O

A

Cl

B

3Cl

C

Cr2O7

D

3MnO

Q11

Short Answer 1 mark

PCl 5 decomposes as shown. PCl 5

Q11(g)

Short Answer 1 mark

PCl 3

Q11(g)

Short Answer 1 mark

+ Cl 2

Q11(g)

Short Answer 1 mark

1.0 mol of PCl 5

Q11(g)

Short Answer 1 mark

, 1.0 mol of PCl 3

Q11(g)

Short Answer 1 mark

and 1.0 mol of Cl 2

Q11(g)

Short Answer 1 mark

are placed in a container of volume at 250 °C and allowed to reach equilibrium. At this temperature, the equilibrium mixture contains 1.8 moles of PCl What is the value of K c at 250 °C? A 1 B 1.8 C 9 D 16.2

Q12

MCQ 1 mark

The fifth to eighth ionisation energies of four elements in Period 3 of the Periodic Table are shown. Which row refers to chlorine? ionisation energies / kJ mol fifth sixth seventh eighth A 6280 21 200 25 900 30 500 B 6990 8 490 27 100 31 700 C 6540 9 330 11 000 33 600 D 7240 8 790 12 000 13 800

A

6280 21 200 25 900 30 500

B

6990 8 490 27 100 31 700

C

6540 9 330 11 000 33 600

D

7240 8 790 12 000 13 800

Q13

Short Answer 1 mark

Magnesium nitrate, Mg(NO 3)2, decomposes when heated to give a white solid and a mixture of gases. One of the gases released is an oxide of nitrogen, X. 7.4 g of anhydrous magnesium nitrate is heated until no further reaction takes place. What mass of X is produced? A 1.5 g B 2.3 g C 3.0 g D 4.6 g

Q14

MCQ 1 mark

Which statement explains why iodine is less volatile than chlorine? A Chlorine is more electronegative than iodine and so has more repulsion between its molecules. B The greater number of electrons in iodine leads to larger temporary dipole-induced dipole forces. C The I-I bond energy is smaller than the Cl -Cl bond energy. D The iodine molecules have stronger permanent dipole-permanent dipole forces.

A

Chlorine is more electronegative than iodine and so has more repulsion between its

B

The greater number of electrons in iodine leads to larger temporary dipole-induced dipole

C

The I-I bond energy is smaller than the Cl

D

The iodine molecules have stronger permanent dipole-permanent dipole forces.

Q15

MCQ 1 mark

Ammonium carbonate is a crystalline solid. On gentle warming a reaction occurs, forming ammonia as one product. How are the carbonate ions behaving during this reaction? A Brønsted-Lowry acid B Brønsted-Lowry base C oxidising agent D reducing agent

A

Brønsted-Lowry acid

B

Brønsted-Lowry base

C

oxidising agent

D

reducing agent

Q16

MCQ 1 mark

One molecule of an oxide of element Z reacts with six molecules of water to produce an acidic compound. What is element Z? A aluminium B phosphorus C silicon D sulfur

A

aluminium

B

phosphorus

C

silicon

D

sulfur

Q17

MCQ 1 mark

Which property shows an increase from magnesium to barium? A the first ionisation energy of the elements B the oxidising power of the metals C the solubility of the hydroxides D the solubility of the sulfates

A

the first ionisation energy of the elements

B

the oxidising power of the metals

C

the solubility of the hydroxides

D

the solubility of the sulfates

Q18

Short Answer 1 mark

A test-tube of HBr

Q18(g)

Short Answer 1 mark

and a separate test-tube of HI

Q18(g)

Short Answer 1 mark

are heated to the same temperature. Which combination of observations is possible? test-tube of HBr

Q18(g)

Short Answer 1 mark

test-tube of HI

Q18(g)

Short Answer 1 mark

A a brown vapour appears no change B a purple vapour appears no change C no change a brown vapour appears D no change a purple vapour appears

Q19

MCQ 1 mark

Most modern cars are fitted with catalytic converters in the exhaust system. Which three gases are removed by a catalytic converter? A carbon monoxide, hydrocarbons, nitrogen oxides B carbon monoxide, carbon dioxide, nitrogen oxides C carbon monoxide, nitrogen oxides, sulfur dioxide D hydrocarbons, nitrogen oxides, sulfur dioxide

A

carbon monoxide, hydrocarbons, nitrogen oxides

B

carbon monoxide, carbon dioxide, nitrogen oxides

C

carbon monoxide, nitrogen oxides, sulfur dioxide

D

hydrocarbons, nitrogen oxides, sulfur dioxide

Q20

Short Answer 1 mark

Compound X is shown. compound X X is treated separately with NaOH(aq) and LiAl H4 to give Y and Z. LiAl H NaOH(aq) What are Y and Z? Y Z ONa ONa

Q21

Short Answer 1 mark

The table shows the molecular formulae of three molecules P, Q and R. None of the molecules are cyclic. molecule molecular formula P CH 4O Q CH 2O2 R CH 2O Which molecules show a strong absorption between 1610 and 1750 cm in their infra-red spectra? A Q only B R only C Q and R only D P, Q and R

Q22

MCQ 1 mark

Which row correctly shows the type of mechanism of each of the two reactions? 2H5Br + KCN CH 3COCH3 + HCN A electrophilic substitution electrophilic addition B electrophilic substitution nucleophilic addition C nucleophilic substitution electrophilic addition D nucleophilic substitution nucleophilic addition

A

electrophilic substitution electrophilic addition

B

electrophilic substitution nucleophilic addition

C

nucleophilic substitution electrophilic addition

D

nucleophilic substitution nucleophilic addition

Q23

Short Answer 1 mark

Ester X is shown. ester X 3CO2(CH2)7CH3 Ester X is hydrolysed using aqueous sodium hydroxide. What is the molecular formula of one of the products?A C 2H4O2 B C 2H3O2Na C C 8H16O D C 8H17O2Na

Q24

MCQ 1 mark

Which reagent could be used to distinguish between propane-1,2-diol and ethane-1,2-diol? A alkaline aqueous iodine B aqueous acidified dichromate(VI) C ethanol and a few drops of concentrated sulfuric acid D sodium metal

A

alkaline aqueous iodine

B

aqueous acidified dichromate(VI)

C

ethanol and a few drops of concentrated sulfuric acid

D

sodium metal

Q25

MCQ 1 mark

Which substance forms propanoic acid as one of the products when it reacts with hot concentrated acidified potassium manganate( VII)? A but-1-ene B but-2-ene C 2-methylpropene D 2-methylbut-1-ene

A

but-1-ene

B

but-2-ene

C

2-methylpropene

D

2-methylbut-1-ene

Q26

Short Answer 1 mark

The structure of damascenone is shown. damascenone Including damascenone, how many stereoisomers exist with this structural formula? A 1 B 2 C 4 D 8

Q27

Short Answer 1 mark

How many isomeric esters have the molecular formula C 4H8O2? A 2 B 3 C 4 D 5

Q28

MCQ 1 mark

Ethene reacts with aqueous bromine to give two products, CH 2BrCH2Br and CH2BrCH2OH. Which statement about these products is correct? A Both products are obtained in this reaction by nucleophilic substitution. B Both products are obtained in this reaction by nucleophilic addition. C Both products can be hydrolysed to form the same organic compound. D Both products can form hydrogen bonds with water.

A

Both products are obtained in this reaction by nucleophilic substitution.

B

Both products are obtained in this reaction by nucleophilic addition.

C

Both products can be hydrolysed to form the same organic compound.

D

Both products can form hydrogen bonds with water.

Q29

MCQ 1 mark

PVC is used as a packaging material. What holds the different polymer strands together in a piece of solid PVC? A covalent bonds B hydrogen bonds C ionic bonds D van der Waals' forces

A

covalent bonds

B

hydrogen bonds

C

ionic bonds

D

van der Waals' forces

Q30

MCQ 1 mark

The diagram shows the structure of buta-1,3-diene. H H buta-1,3-diene The addition reaction between buta-1,3-diene and two molecules of hydrogen bromide can produce three structurally isomeric products. How many of these products have at least one chiral centre? A 0 B 1 C 2 D 3 Section B For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct). The responses A to D should be selected on the basis of A B C D 1, 2 and 3are correct 1 and 2 only are correct 2 and 3 only are correct 1 only correct No other combination of statements is used as a correct response. Use of the Data Booklet may be appropriate for some questions.

A

0 B 1 C 2 D 3

A

B C D

Q31

Short Answer 1 mark

Scientists are trying to synthesise a new element with proton number 119. The element is predicted to be a Group 1 element in Period 8 of the Periodic Table. Which predictions are likely to be correct about this element? 1 The outermost occupied orbital of one atom of this element will be an s orbital. 2 The atomic radius will be the largest of the seven elements in Group 1. 3 It will have a greater first ionisation energy than element 118.

Q32

Short Answer 1 mark

Which reactions would have the reaction profile shown? energy progress of reaction The responses A to D should be selected on the basis of A B C D 1, 2 and 3are correct 1 and 2 only are correct 2 and 3 only are correct 1 only correct No other combination of statements is used as a correct response.

Q33

Short Answer 1 mark

Which factors can lead to an increase in the rate of a reaction? 1 a lower activation energy 2 an increase in temperature 3 an increase in the concentration of a reactant

Q34

Short Answer 1 mark

Sodium and fluorine are both reactive elements. Two atoms are described. F Na atomic number 9 11 nucleon number 19 23 Which statements about these two atoms, and the ions they can form, are correct? 1 One Na atom has two more protons than one F ion. 2 One Na atom has two more neutrons than one F atom. 3 One Na ion has the same number of electrons as one F ion.

Q35

Short Answer 1 mark

In the atmosphere, which transformations can involve sulfur dioxide as either a reagent or a catalyst? 1 NO 2 to NO 2 NO to NO 3 CO to CO

Q36

Short Answer 1 mark

The bond P of the HBr molecule is Q than that of the HI molecule. Which pairs of words correctly complete the above sentence? P Q 1 energy greater 2 length less 3 polarity greater

Q37

Short Answer 1 mark

Compound X has the structure shown. compound X Which statements about compound X are correct? 1 X will decolourise cold, acidified KMnO 4(aq). 2 X gives an orange precipitate with 2,4-DNPH reagent. 3 X does not react with Tollens' reagent.

Q38

Short Answer 1 mark

Propanal reacts with hydrogen cyanide. Which absorptions are present in the infra-red spectrum of the product? 1 a weak absorption in the range 2200-2250 2 a strong absorption in the range 3200-3600 3 a strong absorption in the range 1040-1300

Q39

Short Answer 1 mark

Which alcohols cannot be dehydrated to form alkenes? 1 CH3OH 2 (CH 3)3COH 3 CH 3CH(OH)CH3 The responses A to D should be selected on the basis of A B C D 1, 2 and 3are correct 1 and 2 only are correct 2 and 3 only are correct 1 only correct No other combination of statements is used as a correct response.

Q40

Short Answer 1 mark

A reaction mechanism is shown. Br H Which statements about this reaction are correct? 1 Heterolytic bond fission occurs. 2 It is a substitution reaction. 3 OH behaves as an electrophile. Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.

Board	CAIE
Level	A Level
Subject	Chemistry
Code	`9701`
Year	2020
Session	May/June
Q&A	52 questions

Chemistry 2020 · May/June

Questions & Model Answers 52 Qs

Paper Details