Notesale: Turn your study into money

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IGCSE Chemistry past papers

Contents:
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Definitions:
Uses:
Processes:
Past papers used:
■ Past exams
■ F/M 2016 (42,43,44)
■ M/J 2015 31
■ O/N 2014 61
● Some quite helpful tips I found on the Internet:
■ Paper 6 tips
■ Examiner tips => very, very helpful
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1-Stoichiometry
relative atomic mass: the average atomic mass of naturally occurring atoms of an element on a scale where the
C-12 atom has a mass of exactly 12 units
relative molecular mass: the sum of relative atomic masses
4
...
02 x10^23 particles, molecules, ions or atoms

5-Electricity and chemistry
Electrolysis: the breakdown of an ionic compound, molten or in aqueous solution, by the passage of electricity
7
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4-Redox
oxidation: loss of electrons
reduction: gain of electrons
oxidising agent: a substance which oxidises another substance during a redox reaction
reducing agent: a substance which reduces another substance during a redox reaction
equilibrium: (2) the reactions that take place in both directions (1) are equal (1), causing the macroscopic
properties to stay the same (1)
14
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1-Polymers
Polymer: large molecules built up from small units (monomers)

2

Uses to remember:

❖ Uses of sulfur dioxide: (2)
➢ manufacturing sulfuric acid
➢ as a bleach in the manufacture of wood pulp for paper
➢ food/fruit juice/wine preservative (by killing bacteria)
➢ fumigant/insecticide/sterilising
❖ Uses of sulfuric acid: (2)
➢ paints and dyes
➢ plastics
➢ fertilisers
➢ soaps and detergents
➢ cleaning metals
➢ car batteries
❖ Uses of mild steel (1)
➢ car bodies
➢ machinery
➢ chains
➢ pylons
➢ nails
➢ screws
❖ Uses of high carbon steel (1)
➢ hammers
➢ knives
➢ drills
➢ railway tracks
➢ razor blades
➢ chisels
❖ Uses of low alloy steel: (1)
➢ chains
➢ bridges
➢ high speed tools
❖ Uses of stainless steel: (1)
➢ cutlery
➢ chemical plant
➢ watches
➢ utensils
➢ surgical instruments
➢ cars
➢ sinks
➢ aircraft

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➢ garden tools
❖ Uses of ammonia
➢ manufacture of fertilisers/nylon/nitric acid/cleaning agent/oven cleaner/hair
dye/urea/refrigeration/explosives
❖ Uses of sodium hydroxide
➢ drain cleaner/oven cleaner/extraction of aluminium/purification of bauxite/manufacture of
biodiesel/paper/soap/washing powder/textiles/dyes (1)
❖ Uses of chlorine
➢ treating drinking water/treating water in swimming pools/kills bacteria in water/chlorination
of water/manufacture of paper products/plastics/PVC/dyes/textiles/medicines/antiseptics/
insecticides/herbicides/fungicides/solvents/paints/disinfectant/bleach/hydrochloric acid
❖ Uses of hydrogen
➢ fuel/rocket fuel/fuel cells/in welding/manufacture of ammonia/NH3/margarine/methanol/
hydrochloric acid/refrigerants
❖ State two uses of graphite that depend on the properties below (2)
➢ good conductor of electricity:
- electrodes or brushes in electric motors (1)
➢ is soft:
- pencils or lubricants (or polishes) (1)
❖ Explain the uses of aluminium limited to food containers and the manufacture of aircraft (2)
➢ manufacture of aircraft: because of its strength and low density
➢ food containers: because of its resistance to corrosion
❖ Uses of zinc
➢ making brass/alloys
➢ galvanising
➢ sacrificial protection
➢ batteries
➢ roofing
❖ Uses of copper
➢ electrical wiring
➢ cooking utensils
❖ Uses of calcium carbonate (2)
➢ manufacture of cement
➢ manufacture of iron
➢ neutralising acidic soils/rivers/streams/lakes
Uses of calcium oxide and slaked lime (2)
➢ treating acidic soils
➢ neutralising acidic industrial wastes
➢ flue gas desulfurization
❖ Name the uses of the following fractions (4)
➢ refinery gas: => bottled gas for heating and cooking
➢ gasoline/petrol: => fuel/petrol for cars

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➢
➢
➢
➢
➢
➢

naphtha: => making chemicals
paraffin/kerosene: => jet fuel
diesel oil: => diesel engines
fuel oil: => fuel for ships and home heating systems
lubricating oil: => lubricants, polishes, waxes
bitumen: => making roads
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1- Measurement
2
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1-Criteria of purity
2
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2-Methods of purification
❖ Complete the following sentences using the words from the list below (5)
Fractional distillation is used to separate a mixture of water and ethanol
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The more volatile liquid evaporates and moves up further up
the column
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-condensor
-lower

-crystallisation
-solid

-distillation
-volatile

-flask
-vapor

-heavy

-higher

➢
3
...
(3)

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Particle

Relative mass

Relative charge

Protons

1

+

Neutrons

1

no charge

Electrons

1/1840

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❖ Define the term isotope
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2
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g
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2
...
2
...
2
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Describe the structure of germanium
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2
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1-Stoichiometry
4
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2-Energy transfer
7
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2-Rate of reaction
❖ What is meant by the term catalyst? (2)
➢ (activities substance that) increases the rate of reaction (1) without being changed (1) by
lowering the activation energy (1)
❖ Suggest one method of increasing the rate of reaction (1)
➢ (Adding a) catalyst (1)
➢ increasing the temperature (1)
➢ increasing the surface area/use powder instead (1)
➢ increasing the pressure (1)

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➢ increasing the concentration (1)
❖ Use collision theory to explain why increasing the concentration would change the rate of reaction (2)
➢ more particles per unit volume/particles are close together (1)
➢ increases the rate of collisions (1)
❖ Use collision theory to explain why increasing the temperature would increase the rate of reaction (3)
➢ particles gain more kinetic energy and move faster (1)
➢ which increase the rate of collisions (1)
➢ and more/a higher proportion of, particles have sufficient energy to react / more particles
overcome the activation energy (1)
❖ In an experiment, sodium thiosulfate is reacted with hydrochloric acid
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Suggest why the total
volume must be kept constant (2)
➢ to allow for comparison/to make tests fair (1)
➢ the concentration of the thiosulfate is proportional to the volume of the thiosulfate solution
added/concentration always the same (1)

7
...

BiCl3 (aq) + H2O (l) ⇆ BiOCl (s) + 2HCl (aq)
colorless

white


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Suggest an explanation (2)
■ equilibrium to left or favors backward reaction (1)
■ BiOCl used up or BiCl3
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1-The characteristics of acids and bases
❖ Define the term base (1)

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➢ a proton/H+ acceptor
❖ In terms of proton transfer, explain what is meant by the term weak base (1)
➢ a proton acceptor (1), that doesn’t accept protons that readily (1)
❖ Complete the table below (2)
solution

pH

aqueous ammonia

10

dilute hydrochloric acid

1

sodium hydroxide solution

13

vinegar

4

❖ When nitric acid is added to water the following reaction occurs
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name: proton (1) REJECT hydrogen ion
formula: H⁺ (1)
❖ Explain why solutions of hydrochloric acid and ethanoic acid with the same concentration, in
mol/dm^3, have different pH
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Describe another
method (2)
➢ 1) react it with Ca/Mg/Zn/Fe (1)
➢
Strong acid (HCl) bubbles faster/more (1)
OR
➢ 2) test electrical conductivity (1)
➢
strong acid is a better conductor (1)
OR
➢ 3) measure rate of reaction with metal carbonate (1)
➢
strong acid (HCl) reacts faster/more bubbles/dissolves faster (only if carbonate insoluble) (1)
❖ Suggest a reagent that could be used to displace the weak base, ethylamine, from its salt
ethylammonium chloride (1)
➢ NaOH (1)
❖ Given an aqueous solution of ethylamine, a weak base, and sodium hydroxide, a strong base, describe
how you would show that sodium hydroxide is the stronger base
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The gas was tested
with damp red litmus paper
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Acid rain decreases the pH of the water in lakes and rivers
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Explain
why calcium carbonate is a better choice (2)
➢ calcium oxide soluble in water/reacts with water to form CaOH (1),
➢ causing the pH to rise above 7/water becomes alkaline (1)
OR
➢ calcium carbonate insoluble in water (1)
➢ pH cannot rise over 7/water neutral (1)
❖ Explain why farmers don’t want their crop to become too alkaline (1)
➢ so plants can grow better/so crops can grow better/plants cannot grow well in alkaline
conditions
❖ Complete the word equations for the reactions of ethanoic acid: (2)
➢ calcium + ethanoic acid => calcium ethanoate + hydrogen
➢ zinc oxide + ethanoic acid => zinc ethanoate + water
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It is insoluble in water
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(3)
➢ add a named acid, (e
...
HCl, H2SO4 ) and add a named alkali, (e
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NaOH) (1)
➢ aluminium oxide (Al2O3) will react with/neutralise, both reagents (1), forming a
solution/dissolving in it
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3-Preparation of salts
❖ Complete the table below
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4-Identification of ions and gases
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2-Periodic trends

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A) Predict one physical property of Rubidium which is the same as that of a transition element (1)
conducts heat and/or electricity (1)
malleable (1)
sonorous (1)
ductile (1)
B) Predict two physical properties that are different to those of a transition element such as iron (2)
soft (1)
low melting and/or boiling point (1)
low density (1)
C) When Rubidium is added to cold water, as reaction occurs (1)
i) Suggest two observations that would be made when Rubidium is added to cold water (2)
effervescence (1)
flame (1)
floats (1)
rapid movement (1)
forms as ball (1)
ii) what would be the color of the solution if methyl orange was added to it after the reaction (1)
yellow (1)
iii) Put the Group I elements, caesium, lithium, potassium, sodium and rubidium in the order of their reactivity
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(1)
Caesium, Rubidium, Potassium, Sodium, Lithium (1)
iv) Suggest one safety measure that should be used when rubidium is added to cold water (1)
goggles/gloves/tongs/keep a safe distance (1)
v) Write a chemical equation for the reaction between Rubidium and water (2)
2Rb + 2H2O => 2RbOH + H2

❖ Write a chemical equation for the reaction between magnesium and warm water (2)
➢ Mg + 2H2O => Mg (OH)2 + H2
❖ Describe the test you would use to show that the gas evolved is hydrogen (1)
➢ goes “pop” with burning splint (1)
➢ or mixed with air and ignited goes pop (1)

HALOGENS
❖ How does their color change down the group? (1)
➢ darker (1)
➢ OR
➢ actual colors:
■ fluorine => colorless/pale yellow
■ chlorine => yellow/yellow-green
■ bromide => orange/brown/brownish-red
■ iodine => black/grey/purple
■ (astatine => black)
❖ How does their physical state (solid, liquid or gas) change down the Group? (1)
➢ gas, liquid, solid

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❖ Predict the physical state of astatine (1)
➢ solid (1)
❖ Suggest two similarities in the chemical properties of astatine and fluorine (2)
➢ both form acidic oxides (1)
➢ both have a valency of one (1)
➢ both can react with other elements to form halides (1)
➢ both are oxidants (1)
➢ they both form acidic hydrides (1)
➢ both have diatomic molecules (1)
➢ both react with metals to form ionic compounds (1)
❖ Predict the color and physical state of fluorine (2)
colour: colourless/pale yellow (1)
physical state: gas (1)
❖ The reactivity of halogens decreases down the group
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Include an equation in your answer (3)
➢ add chlorine to iodide solution (1)
➢ the solution turns red/brown/yellow (1)
➢ Cl2 + 2KI => 2KCl +I2
OR
➢ Cl2 + 2I- =>2Cl- +I2
9
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g
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5-Noble gases
10
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2-Reactivity series
10
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Suggest how metal X could be extracted
from its chloride (2)
➢ by electrolysis (1) when molten (1)
EXTRACTION OF IRON
❖ Give one use of ammonia (1)
➢ manufacture of fertilisers/nylon/nitric acid/cleaning agent/oven cleaner/hair
dye/urea/refrigeration/explosives (1)
❖ Write an equation for the exothermic reaction that causes this high temperature of 2000°C
➢ C + O2 = CO2
❖ In the furnace, the ore is reduced by carbon monoxide
...
(3)
➢ higher in furnace, no oxygen is left (1)
➢ carbon dioxide reacts with carbon to form carbon monoxide (1)
➢ CO2 + C = 2CO (1)
❖ Which substance is a mineral containing largely calcium carbonate? (1)
➢ limestone (1)
❖ Which substance is formed when the impurities in the ore react with calcium oxide? (1)
➢ slag/calcium silicate (1)
❖ Which substance is also called hematite? (1)
➢ iron ore
❖ State two functions of coke in the blast furnace (2)
➢ to provide heat/to burn (1)
➢ to make carbon monoxide, (which reduces iron oxide) (1)
❖ The formation of slag removes an impurity in the ore
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Describe how zinc oxide is made from zinc sulfide and write a chemical reaction of this reaction (1)
➢ roast/heat, in oxygen/air (1)
➢ 2ZnS + 3O2 => 2ZnO + 2SO2 (1)

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❖ Explain how zinc oxide is converted into zinc
...
This contains alumina, which is amphoteric, and iron (III) oxide,
which is basic
...
Complete the following sentences
(4):
The alumina/aluminium oxide dissolves to give a solution of sodium aluminate
...

10
...
(1)
➢ reducing the movement/ which interrupts movement (1)
❖ Give an explanation for the following
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1-Water

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❖ Explain why adding chlorine to water makes it safe to drink (1)
➢ kills bacteria (1)
11
...
State the source amd
the harmful
11
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Reference to rate and
yield is not required (5)
➢ 200 atm (allow 150-300 atm) (1)
➢ 450°C (allow tallow 370-470) (1)
➢ iron catalyst (1)
➢ N2 + 3H2 ⇆ 2NH3 (must be balanced) (1)
➢ (reaction is) reversible/in equilibrium (1)
❖ Describe how hydrogen is obtained for the modern process (2)
➢ from methane (1) and water (1)
OR
➢ electrolysis (1) using a suitable electrolyte (1) e
...
dilute aqueous solution of NaCl
OR
➢ cracking (1) of alkenes (1)
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(1)
➢ bleaching in the manufacture of wood pulp for paper/straw/wool/cotton (1)
➢ food preservative or killing bacteria in food or wine (1)
➢ fumigant
➢ refrigerant
➢ tanning leather
❖ Name a source of sulfur (1)
➢ (sulfur containing) fossil fuels (1)
❖ Describe step 2 (sulfur dioxide => sulfur trioxide), giving reaction conditions and a chemical equation
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1-Names of compounds
14
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Name two other fossil fuels (2)
➢ petroleum (1)
➢ natural gas/methane (1)
➢ petrol (1)
➢ kerosene (1)
➢ diesel (1)
➢ fuel oil (1)
➢ propane (1)
➢ butane (1)
➢ crude oil (1)
➢ refinery gas (1)
❖ Name a gaseous fossil fuel (1)
➢ methane (1)
➢ natural gas (1)
➢ propane (1)

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➢
➢
➢
➢

butane (1)
petroleum gases (1)
calor gas (1)
refinery gas (1)

❖ Name a solid fossil fuel (1)
➢ coal or coke or peat (1)
❖ Name two liquid fuels obtained from petroleum (2)
➢ petrol/gasoline (1)
➢ paraffin/kerosene (1)
➢ diesel (1)
➢ jet fuel/aviation fuel (1)
➢ fuel oil (1)
➢ heavy fuel oil (1)
➢ heating oil (1)
❖ Name two other useful products obtained from petroleum that are not used as fuels (2)
➢ naphtha (1)
➢ bitumen (1)
➢ waxes (1)
➢ grease (1)
➢ polishes (1)
➢ lubricants (1)
❖ Name two industrial processes which must take place to produce alkenes from petroleum (2)
➢ fractional distillation (1)
➢ cracking (1)
❖ Give another mixture of liquids that is separated on an industrial scale by fractional distillation (1)
➢ liquid air (1)
➢ ethanol and water (1)
➢ alkenes made by cracking (1)
➢ noble gases (1)
14
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4-Alkanes
14
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➢ Test: Add bromine water
➢ Result: From brown to colourless
14
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7-Carboxylic acids
❖ State the name of the ester formed from butanol and ethanoic acid (1)
➢ Butyl ethanoate (1)
❖ State the name of the product formed, when But-1-ol is oxidised by potassium manganese (VII) (1)
➢ Butanoic acid (1 )
14
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1-Polymers
❖ What type of polymerisation takes place when ethene forms a polymer? (1)
➢ addition (1)
❖ What type of polymerisation takes place when propene is polymerised to form polypropene? (1)
➢ addition (1)
❖ What is the empirical formula of the polymer formed from ethene (1)
➢ CH2
❖ Give the empirical formula of: (2)
➢ propene: CH2
➢ polypropene: CH2
❖ Deduce the maximum mass of polypropene that could be produced from 1kg of propene (1)
➢ 1kg (1)
14
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2-Synthetic polymers
❖ Name the catalyst needed to form an ester from ethanoic acid and methanol (1)
➢ concentrated sulfuric acid (1)
❖ Name the ester formed when ethanoic acid reacts with methanol (1)
➢ methyl ethanoate (1)
❖ Give the name of a polyester (1)
➢ terylene (1)
❖ Suggest a use for terylene (1)
➢ ropes (1)

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➢
➢
➢
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clothing (1)
bottles (1)
packaging (1)
bags (1)

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3-Natural polymers
❖ When separating amino acids, explain why the chromatogram must be exposed to a locating agent
before Rf values can be measured, (1)
➢ because acids are colorless or to make them visible or to show positions of the samples or
distance travelled (1)
❖ Measuring pH is is one way of identifying amino acids on a chromatogram
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blogspot
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html

Contains some good points
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1) What is the purpose of ice or cold water? To cool down the gas so that it condenses and turns into a liquid
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It is less dense than air
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4) When using ethanol, give a better apparatus arrangement, and why? Cover apparatus with a lid, because
ethanol is volatile
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6) when copper is used in the test, and the answer is four marks, the best answer is: light blue precipitate (ppt)
which is soluble in excess to form dark blue solution
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It is toxic
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9) Why should the solid be crushed? It increases surface area for a faster rate of reaction
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11) explain the term (decant)
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12) Why is concentrated sulphuric acid not used to dry ammonia? Because it will react with the base ammonia,
which is neutralization reaction
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14) Suggest why it is important to know the pH of the soil
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15) What is necessary for rusting? Water (humidity) and oxygen (air)
...
Oxygen is used up, and water is used to
take its place
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The bulb will light - A metal is formed on the cathode - Fizz of gases
produced
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Graphite - Carbon - Steel-Platinum
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20) How can you distinguish between water and ethanol? Use cobalt chloride paper, it turns from pink to blue
with water, but there will be no change with ethanol
...
You can add a metal, in which hydrogen is produced with sulphuric acid, but no
change in sodium sulphate
...

22) how can you distinguish between hydrochloric acid and nitric acid? Add silver nitrate, in which white ppt
will be formed with hydrochloric acid, but there will be no reaction with nitric acid
...

24) When there is a delivery tube involved in a question, what precaution should be taken in the experiment
when the heat is removed? Remove the delivery tube from water to prevent suck-back
...

26) How can you distinguish between alkanes and alkane? Use bromine water, in which the alkene will
decolourise it to colorless, but nothing happens with an alkane,
27) how can you distinguish between chlorine and sodium chloride? Add litmus paper, it will bleach with
chlorine, but nothing happens to it with sodium chloride
...
OR just add
hydrochloric acid, in which nothing happens with sulphate, but a fizz or effervescence of carbon dioxide will
occur with carbonate
...

30) volume of reagent used decreases if it is more concentrated
...
A strong acid lies between pH values of 0 and 2, and a weak one lies between 3 and
6
...
A weak base lies between 8 and 11, while a strong one lies between 12 and 14
...
Vice versa with dilute
acid
...
Vice versa with dilute
base
...
Vice versa with a weak one
...
Vice versa with a weak one
...

37) How can you make crystals? 1)heat till point of crystallization
...
3) filter, dry and
collect the crystals!
38) How can you detect the point of crystallization? Place a stirring rod in the solution and see the formation of
the first crystals on it
...

40) Grass is ground with ethanol rather than water because chlorophyll is more soluble in ethanol
...

43) you can speed up the drying process by using a fan or by increasing temperature or by using a hair-drier if
you have one

) , NOT a catalyst
...

45) to check for the purity for a collected solvent, test it's melting or boiling point
...

47) If water contained salt, this will have no effect on rusting, however if a bigger substance is being rusted, it
will be slower
...

49) saturated: no more solute can be dissolved in a solvent AT A CONSTANT TEMPERATURE
...

51) Sometimes, crystals are dried using filter paper instead of heating to prevent the complete loss of water from
crystals, and to prevent crystals from breaking
...

53) excess means more than what is needed
...

55) to separate two different solutions with different boiling point, use fractional distillation
...

57) chemical test of water: Add blue cobalt chloride paper, it turns pink OR add anhydrous copper sulphate, it
turns blue
...
Lagging or cloth can be used to control temperature for accurate results
...

60) As reactants are heated, the particles gain energy, move faster, and their kinetic energy increases therefore
there will be more collisions and rate increases
...
com/uploads/3/0/6/6/3066260/examiner_tips_for_igcse_chemistry_0620_final
...
gceguide
...
pdf
Unfortunately there are no answers available, but they are exam-style, so you
might want to just skim over it to see if there are any challenging questions, and
you could try them
...


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