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ZIMSEC O Level · 4024/1 · N2020

Chemistry Paper 1 November 2020

Questions
40
Time allowed
60 min
Syllabus code
4024/1

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Questions
40
Pass mark
24
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Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 1

Atomic structure

The table shows information about the subatomic particles of two species, X and Y.

elementnumber of electronsnumber of neutronsnumber of protons
X465
Y645

Which statement about X and Y is correct?

  1. AThey are both positively charged.
  2. BThey have the same mass number.
  3. CThey represent the same element.
  4. DThey are both negatively charged.

Question 2

Atomic structure

What is the correct number of subatomic particles in the ion 90/38 Z 2+?

protonsneutronselectrons
A385240
B385236
C523840
D523836
  1. AA
  2. BB
  3. CC
  4. DD

Question 3

Atomic structure

The table shows information about particles of two elements, M and N.

elementnumber of protonsnumber of neutronselectronic structure
M9102.8
N17202.8.8

Which statement is correct for both M and N?

  1. AThey are isotopes of the same element.
  2. BThey are negatively charged ions.
  3. CThey are atoms of noble gases.
  4. DThey are positively charged ions.

Question 4

Particulate nature of matter
Which factor affects the rate of diffusion of a gas?
  1. Ainertness
  2. Bsolubility
  3. Ccolour
  4. Dmolecular mass

Question 5

Rates of reaction
Increasing the temperature of a reaction mixture increases the rate of reaction because
  1. Aparticles gain kinetic energy and collide more frequently.
  2. Bparticles lose kinetic energy and collide less frequently.
  3. Cparticles gain kinetic energy and collide less frequently.
  4. Dparticles lose kinetic energy and collide more frequently.

Question 6

Particulate nature of matter
Which statement is not true about the properties of particles of matter?
  1. Aparticles in a liquid have less energy than particles in a gas
  2. Bparticles in a solid have less energy than particles in a liquid
  3. Cparticles in a gas have less energy than particles in a solid
  4. Dparticles in a liquid have more energy than particles in a solid

Question 7

Periodic table

An element, X, in its ground state, is a diatomic gas and has seven valence electrons.

Element X is

  1. Ahelium.
  2. Boxygen.
  3. Cchlorine.
  4. Dnitrogen.

Question 8

Acids, bases and salts

A volume of 20.00 cm3 of 0.20 moldm-3 hydrochloric acid were reacted with potassium hydroxide solution.

What was the concentration of the hydroxide if 15.00 cm3 were needed for complete neutralisation?

  1. A0.27 moldm-3
  2. B1.33 moldm-3
  3. C4.00 moldm-3
  4. D0.03 moldm-3

Question 9

Rates of reaction
Which statement is not correct about the reaction between calcium carbonate and excess hydrochloric acid.
  1. AThe reaction can be speeded up by using powdered calcium carbonate.
  2. BThe reaction can be slowed down by using cold acid.
  3. CThe reaction can be speeded up by using dilute acid.
  4. DHalf the volume of gas is produced if half the mass of calcium carbonate is used.

Question 10

Bonding and structure
Which set of elements exist as diatomic molecules?
  1. Anitrogen, flourine, neon
  2. Bhydrogen, chlorine, neon
  3. Coxygen, chlorine, helium
  4. Doxygen, hydrogen, nitrogen

Question 11

Energy changes
An endothermic reaction occurs when
  1. Athe products are more stable than the reactants.
  2. Bthe reactants have more energy than the products.
  3. Cbonds are formed.
  4. Dbonds are broken.

Question 12

Bonding and structure

An ionic compound has the formula MX2.

Which row correctly shows the Groups of the Periodic Table to which the elements represented by M and X belong?

MX
AVIIII
BIIVII
CIIII
DVIIII
  1. AA
  2. BB
  3. CC
  4. DD

Question 13

Environmental chemistry
Which statement is not true about eutrophication?
  1. AIt is caused by washing of excess fertilizers into water bodies.
  2. BIt results in increased growth of algae and other aquatic plants.
  3. CIt reduces the amount of oxygen available to fish and other aquatic animals.
  4. DIt can be reversed by reducing the number of organisms that need oxygen.

Question 14

Extraction of metals

Extraction of copper consists of four main stages.

What is the correct sequence of these stages?

  1. Acrushing, flotation, smelting, electrolysis
  2. Bsmelting, crushing, flotation, electrolysis
  3. Celectrolysis, smelting, crushing, flotation
  4. Dflotation, crushing, smelting, electrolysis

Question 15

Fuels
Hydrogen gas is becoming very popular as a fuel mainly because hydrogen
  1. Ais very flammable.
  2. Bis more efficient.
  3. Cis cheaper to produce.
  4. Dproduces less pollutants.

Question 16

Electrolysis
The gas produced at the anode, during the electrolysis of dilute sulphuric acid, can be identified by
  1. Adipping a burning wooden splint into the gas.
  2. Bdipping damp blue litmus paper into the gas.
  3. Cbubbling the gas through limewater.
  4. Ddipping a glowing wooden splint into the gas.

Question 17

Stoichiometry

An organic compound has 92.3 % carbon and 7.7 % hydrogen by mass.

The empirical formula of the compound is

  1. AC3H5.
  2. BC2H3.
  3. CCH2.
  4. DCH.

Question 18

Periodic table
When chlorine gas is bubbled through a colourless solution of sodium bromide, the mixture turns reddish brown because
  1. Achlorine gas is red in solution.
  2. Bchlorine is displaced from the solution.
  3. Cbromine is displaced from the solution.
  4. Dthe two elements have the same reactivity.

Question 19

Stoichiometry

The equation for the reduction of iron oxide by carbon monoxide in the blast furnace is:

Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g)

What mass of iron oxide is needed to produce 56 g of pure iron?

  1. A80 g
  2. B112 g
  3. C160 g
  4. D320 g

Question 20

Redox
Which reaction is not a redox reaction?
  1. A2Fe + 3Cl2 -> 2FeCl3
  2. B2FeCl2 + Cl2 -> 2FeCl3
  3. CFe + 2HCl -> FeCl2 + H2
  4. DFe2O3 + 6HCl -> 2FeCl3 + 3H2O

Question 21

Extraction of metals
Which process is not done during the extraction of nickel ?
  1. Aelectrolysis of nickel chloride with impure nickel as the anode
  2. Belectrolysis of nickel chloride with impure nickel as the cathode
  3. Croasting the sulphide ore to get the oxide
  4. Dreacting the impure nickel with carbon monoxide

Question 22

Metals

Ship bodies made of steel can be prevented from corrosion by fixing a block of another metal to the ship body.

Which metal would not prevent corrosion if used?

  1. Acopper
  2. Bmagnesium
  3. Caluminium
  4. Dzinc

Question 23

Separation techniques
What is the best way of obtaining water from a salt solution?
  1. Aevaporation
  2. Bsimple distillation
  3. Cdecanting
  4. Dfractional distillation

Question 24

Organic chemistry

Ethanoic acid reacts with ethanol to form ethylethanoate.

Which row gives the correct name of the reaction and the correct condition for the reaction?

  1. Aesterification, acidic
  2. Bneutralisation, acidic
  3. Cesterification, alkaline
  4. Dneutralisation, alkaline

Question 25

Acids, bases and salts
Which substance is not suitable for the removal of a salt cake deposited on the element of a kettle by hard water?
  1. Adilute hydrochloric acid
  2. Bvinegar
  3. Clemon juice
  4. Dbicarbonate solution

Question 26

Environmental chemistry
What problem is associated with the incineration of refuse on a large scale?
  1. Aincreases eutrophication
  2. Ban increase in acid rain
  3. Cincreases costs
  4. Dozone layer thickens

Question 27

Stoichiometry

The equation for the complete combustion of butane is:

C4H10 + 13/2 O2 -> 4CO2 + 5H2O

What volume of carbon dioxide is produced from the complete combustion of 58 g of butane at r.t.p?

  1. A28.00 dm3
  2. B7.00 dm3
  3. C112.00 dm3
  4. D35.00 dm3

Question 28

Acids, bases and salts
Which substance is insoluble in water?
  1. Acalcium carbonate
  2. Bmagnesium oxide
  3. Cammonium chloride
  4. Dsodium chloride

Question 29

Stoichiometry
Which gas contains the same number of molecules as 9 g of water?
  1. A2 g of hydrogen
  2. B14 g of nitrogen
  3. C32 g of oxygen
  4. D44 g of carbon dioxide

Question 30

Organic chemistry
Two different hydrocarbons with the same percentage by mass of hydrogen will have the same,
  1. Aempirical formula.
  2. Bnumber of isomers.
  3. Crelative molecular mass.
  4. Dstructural formula.

Question 31

Electrolysis

The diagram shows the plating of an iron rod. Electrode V is connected to the positive terminal, electrode W to the negative terminal, and M is the solution in the beaker.

Which materials are used for W, V and M?

WVM
Aironcoppercopper sulphate
Bironcopperiron sulphate
Ccopperironcopper sulphate
Dcopperironiron sulphate
  1. AA
  2. BB
  3. CC
  4. DD

Question 32

Electrolysis
The electrical conductivity of pure water can be improved by the addition of
  1. Amagnesium oxide.
  2. Biron (III) oxide.
  3. Caluminium oxide.
  4. Dpotassium oxide.

Question 33

Fuels
Which is a non-pollutant fuel?
  1. Apetrol
  2. Bhydrogen
  3. Cmethane
  4. Ddiesel

Question 34

Organic chemistry
Which material is not a synthetic polymer?
  1. Apolythene
  2. Bterylene
  3. Crubber
  4. Dnylon

Question 35

Redox

A small quantity of acidified KMnO4 was added to a solution of KI in a test tube.

Which observation was made?

  1. Ano observable change
  2. Bpurple colour
  3. Cwhite precipitate
  4. Dyellow colour

Question 36

Acids, bases and salts

A dilute acid, X, was reacted with different substances as shown:
(i) X + magnesium
(ii) X + copper
(iii) X + sodium carbonate

Which reactions are possible?

  1. A(i), (ii) and (iii)
  2. B(i) and (iii) only
  3. C(ii) and (iii) only
  4. D(i) and (ii) only

Question 37

Acids, bases and salts
Which equation represents the preparation of sodium sulphate by a titration method?
  1. A2NaOH(s) + H2SO4(aq) -> Na2SO4(s) + 2H2O(l)
  2. B2NaOH(aq) + H2SO4(aq) -> Na2SO4(aq) + 2H2O(l)
  3. C2NaOH(s) + H2SO4(aq) -> Na2SO4(aq) + 2H2O(l)
  4. D2NaOH(l) + H2SO4(l) -> Na2SO4(l) + 2H2O(l)

Question 38

Environmental chemistry
Which statement is not true about the activity of microorganisms during the treatment of sewage?
  1. ABacterial activity is increased by bubbling air through the waste.
  2. BAn active food chain always exists in the waste sludge.
  3. CBacteria feed on chemicals and detergents to improve the efficiency of the process.
  4. DMethane gas is a product of the process.

Question 39

Qualitative analysis

The table describes tests carried out on a solution and observations made.

test(s)observation(s)
to a portion of the solution, excess NaOH(aq) was addedwhite precipitate soluble in excess
to a portion of the solution, excess NH4OH(aq) was addedwhite precipitate soluble in excess
to a portion of the solution, AgNO3(aq) was addedwhite precipitate

The solution could be

  1. AZnI2.
  2. BZnCl2.
  3. CAlI3.
  4. DFeCl2.

Question 40

Chemistry in society
Which one is a disadvantage of herbal medicines in comparison to pharmaceutical drugs?
  1. Aineffective
  2. Black of dosage instructions
  3. Cthey have many side effects
  4. Dthey are very expensive

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