ZIMSEC O Level Chemistry Paper 1 November 2018

Question 1

Chromatography

An investigation to identify the ink used to make a fake one hundred dollar note using paper chromatography was carried out. The chromatogram shown was obtained.

The dye(s) present in the fake note are/were

A3, 4 and 5
B2 and 3
C6 only
D3 and 4

Question 2

Atomic structure

Which pair correctly describes the structure of an atom?

Aorbiting the nucleus: protons; in the nucleus: electrons and neutrons
Borbiting the nucleus: electrons and neutrons; in the nucleus: protons
Corbiting the nucleus: electrons; in the nucleus: protons and neutrons
Dorbiting the nucleus: protons and neutrons; in the nucleus: electrons

Question 3

Atomic structure

What is the electronic configuration of the silicon isotope,

^{30}_{14}

Si?

A2. 8. 4
B4. 8. 2
C2. 8. 8. 8. 4
D8. 4. 2

Question 4

Ionic bonding

Which row correctly gives the physical properties of an ionic compound?

Amelting point high; conductivity when solid none; conductivity when molten none
Bmelting point low; conductivity when solid conducts; conductivity when molten conducts
Cmelting point high; conductivity when solid none; conductivity when molten conducts
Dmelting point low; conductivity when solid none; conductivity when molten none

Question 5

Chemical bonding

The table shows the atomic numbers of two elements, P and Q.

Element P has atomic number 19; element Q has atomic number 17.

Elements P and Q can combine to form

Aa covalent compound PQ.
Ba covalent compound PQ $_2$ .
Can ionic compound PQ.
Dan ionic compound PQ $_2$ .

Question 6

Ionic bonding

What is the correct formula of the compound formed between M

^+

and Z

^{2-}

AMZ
BMZ $_2$
CM $_2$ Z
DM $_2$ Z $_2$

Question 7

Covalent bonding

Which structure correctly shows the bonding in carbon dioxide?

Question 8

Solutions and concentration

A 0.1 mol dm

^{-3}

solution of sodium carbonate can be prepared by dissolving

A106 g of Na $_2$ CO $_{3(s)}$ in 100 cm $^3$ of water
B10.6 g of Na $_2$ CO $_{3(s)}$ in 100 cm $^3$ of water
C10.6 g of Na $_2$ CO $_{3(s)}$ in 1000 cm $^3$ of water
D106 g of Na $_2$ CO $_{3(s)}$ in 1000 cm $^3$ of water

Question 9

Ionic equations

Phosphoric acid and potassium hydroxide react according to the equation:

H $_3$ PO $_{4(aq)}$ + 3KOH $_{(aq)}$ $\rightarrow$ K $_3$ PO $_{4(aq)}$ + 3H $_2$ O $_{(l)}$

Which ions will not appear in the ionic equation?

AH $^+_{(aq)}$ and OH $^-_{(aq)}$
BK $^+_{(aq)}$ and PO $_4^{3-}{}_{(aq)}$
CH $^-_{(aq)}$ and PO $_4^{3-}{}_{(aq)}$
DK $^+_{(aq)}$ and OH $^-_{(aq)}$

Question 10

Which equation does not result in a change of oxidation state of the species involved?

AFe $^{2+}_{(aq)}$ $\rightarrow$ Fe $^{3+}_{(aq)}$ + e $^-$
BCu $^{2+}_{(aq)}$ + CO $_3^{2-}{}_{(aq)}$ $\rightarrow$ CuCO $_{3(s)}$
C2H $_{2(g)}$ + O $_{2(g)}$ $\rightarrow$ 2H $_2$ O $_{(l)}$
DAg $^+_{(aq)}$ + e $^-$ $\rightarrow$ Ag $_{(s)}$

Question 11

Energy changes

The production of carbohydrates during photosynthesis is an example

Aan endothermic reaction.
Ba combustion reaction.
Can exothermic reaction.
Da displacement reaction.

Question 12

Sulphur dioxide reacts with oxygen according to the equation:

2SO $_{2(g)}$ + O $_{2(g)}$ $\rightleftharpoons$ 2SO $_{3(g)}$ $\Delta$ H = -188 kJ/mol

Which factor increases the amount of sulphur trioxide produced?

Aincrease in temperature
Bdecrease in temperature
Cincrease in amount of catalyst
Ddecrease in pressure

Question 13

Reactivity series

A new element has been discovered and is believed to be between zinc and lead in the electrochemical series.

How will the element react with solutions of zinc sulphate and lead nitrate?

Azinc displaced; lead remains in solution
Bzinc remains in solution; lead displaced
Czinc displaced; lead displaced
Dzinc remains in solution; lead remains in solution

Question 14

Carbonates

When heated, a metal carbonate decomposes to form

Ametal oxide and carbon
Bcarbon dioxide and metal
Ccarbon monoxide and metal oxide
Dcarbon dioxide and metal oxide

Question 15

Air

Nitrogen and oxygen are separated from liquid air by the process of

Aliquefaction
Bsolidification
Cfractional distillation
Dcondensation

Question 16

Qualitative analysis

Which reagent could be used to distinguish between aluminium nitrate and zinc nitrate?

Asodium hydroxide solution
Bammonia solution
Cbarium chloride solution
Dsilver nitrate solution

Question 17

Empirical formula

A compound of nitrogen and hydrogen contains 87.5 % nitrogen.

What is its empirical formula?

AN $_2$
BNH $_2$
CN $_2$ H $_2$
DN $_2$ H $_4$

Question 18

Air

Respiration, combustion and rusting are chemical processes which all use

Awater.
Bheat energy.
Ccarbon dioxide.
Doxygen.

Question 19

Transition metals

Which one is not a property of transition metal ions?

AThey act as catalysts.
BTheir solutions are colourless.
CTheir solutions are coloured.
DThey have many oxidation states.

Question 20

Extraction of metals

Which pair correctly matches a metal and its extraction method?

Airon -- electrolysis
Bplatinum -- reduction
Cgold -- electrolysis
Dnickel -- reduction

Question 21

Extraction of metals

In the blast furnace, molten iron is tapped off at the bottom of the furnace while slag settles above the molten iron because

Aslag is more dense than molten iron.
Bslag is less dense than molten iron.
Cmolten iron and slag have the same density.
Dmolten iron occupies more space than slag.

Question 22

Metals

Copper metal is used in electrical wiring and manufacture of pots and pans because of its

Ahigh conductivity
Bhigh reactivity
Ccheap cost of production
Dabundance in nature

Question 23

Which structures represents the same compound?

A2 and 4
B1 and 2
C1 and 3
D2 and 3

Question 24

Organic chemistry

Which homologous series of organic compounds has the general formula C

_n

_{2n}

Aalcohols
Bcarboxylic acids
Calkanes
Dalkenes

Question 25

Organic reactions

When two molecules react to form one molecule, this is

Aan addition reaction.
Ba substitution reaction.
Ca condensation reaction.
Dan esterification reaction.

Question 26

Organic chemistry

Ethene may be manufactured according to the reaction:

C $_2$ H $_6$ $\xrightarrow{\text{heat}}$ C $_2$ H $_4$ + H $_2$

What type of reaction is this?

Apolymerisation
Bcracking
Caddition
Dhydrogenation

Question 27

Organic chemistry

Which one is an example of a saturated hydrocarbon?

Abutane
Bethanol
Cbutene
Dbutanol

Question 28

Esters

Which compounds react to form ethylethanoate?

Aethane and ethanol
Bethanoic acid and ethanol
Cethene and ethanoic acid
Dethane and ethanoic acid

Question 29

Polymers

Which structural formula represents nylon?

Question 30

Polymers

Which monomer unit polymerises to form starch?

Question 31

Water treatment

Which process describes the secondary stage of sewage treatment?

Asedimentation
Bsludge activation
Cprecipitation
Ddischarge

Question 32

Water pollution

Which ion is common to both sewage and fertilizers?

Anitrate
Bcarbonate
Cchloride
Dsulphate

Question 33

Air pollution

Which process increases the amount of sulphur dioxide in the air?

Aburning methane
Bburning coal
Cburning wood
Dburning ethene

Question 34

Air pollution

Which pair correctly matches a pollutant gas and its effect on the environment?

ASO $_2$ -- depletes the ozone layer
BNO $_2$ -- global warming
CCFC -- form photochemical smog
DCO $_2$ -- global warming

Question 35

Air pollution

Oxides of nitrogen are produced in car engines because the

Abonds in nitrogen gas are easy to break.
Breactions can take place without interference.
Ccar engines have high temperatures for this reaction.
Dreaction only need moderate warmth to proceed.

Question 36

Waste management

All of the following are used in waste management except

Acomposting.
Bsource reduction.
Cincineration.
Dlogging.

Question 37

Charcoal is used in the purification of water because it

Acoagulates the water.
Bremoves inorganic ions.
Cmakes water colourless.
Ddisinfects the water.

Question 38

Energy changes

The diagram shows the energy profile for the reaction

N $_{2(g)}$ + O $_{2(g)}$ $\rightarrow$ 2NO $_{(g)}$ .

What is the energy change X?

Aenthalpy of combustion
Bbond energy
Centhalpy of reaction
Dactivation energy

Question 39

Medicines

Which one is an advantage of using herbal medicines?

Aherbal medicines cure better than pharmaceutical medicines.
Bherbal medicines are easily metabolized because they are organic.
Cherbal medicines are cheaper than pharmaceutical medicines.
Dherbal medicines have clear directions for use.

Question 40

Fuels

Which chemical process takes place during the production of biodiesel?

Aesterification
Baddition
Chydrogenation
Dcombustion

Chemistry Paper 1 November 2018

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The questions

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Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

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Question 17

Question 18

Question 19

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Question 21

Question 22

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Question 26

Question 27

Question 28

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Question 31

Question 32

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