Questions and Answers of Cambridge IGCSE Chemistry

What are the advantages and disadvantages of the two methods used to manufacture ethanol:a. By fermentationb. By the hydration of ethene with steam?
a. Name the polymerisation process that is used to make both nylon and Terylene.b. Name the starting materials for making: (i) Nylon(ii) Terylene.c. Give the name and formula of the small
a. Which carboxylic acids and alcohols would you use to make the following esters?(i) Butyl methanoate(ii) Ethyl methanoate(iii) Propyl propanoateb. Which esters would be made using the following
Why is it safe for us to use vinegar, which contains ethanoic acid, on food while it would be extremely dangerous for us to use dilute nitric acid for the same purpose?
a. Copy the following table and complete it by writing the structural formulae for methanol and methanoic acid.b. Describe a simple chemical test that could be used to distinguish methanol from
a. Name and give the formula and one use of each of the substances A to D.b. Write word and balanced chemical equations for the reactions involved in the formation of liquids B, C and D.c. Starch is
A piece of cheese contains protein. Proteins are natural polymers made up of amino acids. There are 20 naturally occurring amino acids. The structures of two amino acids are shown below.a. Name the
a. A detergent molecule may be represented by the following simplified diagram.Use this representation of a detergent molecule in a series of labelled diagrams to show how detergents can remove
Explain the following.a. The problem of plastic waste has been overcome.b. The majority of detergents produced today are biodegradable.c. In bread making, yeast is added to the mix and the dough left
a. Which of the following formulae represent alkanes, which represent alkenes and which represent neither?CH3, C6H12, C5H12, C6H6, C9H20, C12H24, C20H42, C2H4, C8H18, C3H7b. Draw all the possible
a. A hydrocarbon contains 92.3% by mass of carbon. Work out the empirical formula of this hydrocarbon.b. The relative molecular mass of this hydrocarbon was found by mass spectrometry to be 78. Work
Crude oil is an important source of organic chemical fuels. It is refined by fractional distillation. Use the information in the table below to answer the questions which follow.Fraction
Alkanes and alkenes are hydrocarbons. They are composed of molecules which contain covalent bonds. For each of the molecules below, use a dot and cross diagram to show the bonding it contains.a.
a. Ethene, C2H4, is the starting material for making plastic carrier bags.(i) Name the type of chemical change taking place in the diagram above.(ii) Name the product formed by this reaction.(iii)
a. Crude oil is a mixture of hydrocarbons which belong to the homologous series called the alkanes. This mixture can be separated into fractions by the process of fractional distillation. Some of the
The following question is about some of the reactions of ethene.a. Give the names and formulae for substances A to F.b. (i) Write a word and balanced chemical equation to represent the reaction in
Explain the following.a. Ethene is called an unsaturated hydrocarbon.b. The cracking of larger alkanes into simple alkanes and alkenes is important to the petrochemical industry.c. The conversion of
Lime (calcium oxide) is produced in very large quantities in a lime kiln. The equation for the reaction is:CaCO3(s) → CaO(s) + CO2(g)a. How much limestone would be needed to produce 61.60 tonnes of
Use the words and formulae below to complete the following passage about limestone and its uses.Limestone is a very common rock. The main chemical in limestone is _________ carbonate (chemical
a. Give the names and formulae of the two major greenhouse gases.b. Name a natural source of the gases you have named in part a.c. Name a man-made source of the gases you have named in part a.
The following question is about carbon dioxide.a. Name and give the formula of each of the substances A, B and C.b. Identify by name the different pieces of apparatus D, E, F and G.c. Draw and label
a. Name and give the formulae of substances A to E.b. Write balanced chemical equations for the reactions in which compounds B, C and E were formed.c. Where would you expect to find acid A?d.
Limestone is an important raw material used in many different industries.a. One of the properties of limestone is that it reacts with acids.(i) Why do farmers spread powdered limestone on their
The diagram shown below is a simplified version of the carbon cycle.a. Name the processes A, B, C and D.b. Write balanced chemical equations to represent the processes taking place in A and B.c.
This question is about the limestone cycle.a. Name and give the formula of:(i) Compound A (ii) Compound B.b. Write balanced chemical equations for the formation of both compounds A and B.c. Name
Sulfuric acid is manufactured by the Contact process, in which a mixture of sulfur dioxide and excess air, preheated to 450°C, is passed over a catalyst.a. How is the sulfur dioxide made? Give an
Describe how you would prepare some crystals of hydrated copper(ii) sulfate from copper(ii) oxide and dilute sulfuric acid. Draw a diagram of the apparatus you would use and write a balanced chemical
In a neutralisation experiment, 25 cm3 of dilute sulfuric acid was required to react completely with 40 cm3 of a solution of 0.25 mol dm−3 potassium hydroxide.a. Write a balanced chemical equation
Study the following reaction scheme:a. Identify the substances A to F by giving their names and formulae.b. Write a balanced chemical equation for the formation of gas B.c. (i) Describe a chemical
Fossil fuels, such as oil, coal and natural gas, all contain some sulfur. When these fuels are burned they produce many different gases. Concern has grown in recent years about the effects of one of
A type of coal contains 0.5% of sulfur by mass.a. Write an equation for the formation of sulfur dioxide gas when this coal is burned.b. What mass of sulfur is contained in 1500 tonnes of coal?c. What
Explain the following.a. Chemical plants that produce sulfuric acid are often located on the coast.b. Even though more sulfuric acid could be produced using high pressures, normal atmospheric
Sulfur has an atomic number of 16 and it is represented as:3216Sa. How many electrons, protons and neutrons does a sulfur atom contain?b. How many electrons will there be in the outer shell (energy
A town’s water supply is obtained by purifying river water.a. What are the A and B in the diagram of the water cycle below?b. (i) Filtration or distillation – which of these processes would
The results of testing five samples of water from different areas are shown in the table below. The soap solution was gradually added to 25 cm3 of each sample of water with shaking until a permanent
Explain the following.a. Industry normally requires water which has been softened.b. Hard water is good for the promotion of healthy bones and teeth.c. Hard water causes kettles to fur. This
Ammonia gas is made industrially by the Haber process, which involves the reaction between the gases nitrogen and hydrogen. The amount of ammonia gas produced from this reaction is affected by both
a. Copy and complete the above table by calculating the percentage of nitrogen in the fertilisers sodium nitrate and potassium nitrate.(Ar: H = 1; N = 14; O = 16; Na = 23; K = 39; Ca = 40)b.
a. Explain what is meant by the term ‘pollution’ with reference to air and water.b. (i) Name an air pollutant produced by the burning of coal.(ii) Name a different air pollutant produced by the
Use the words below to complete the following passage about limestone and its uses.Water is ________ for all life on Earth. It is the most _________ substance on Earth. Water is not only used for
Explain the following.a. Air is a mixture of elements and compounds.b. The percentage of carbon dioxide in the atmosphere does not significantly vary from 0.04%.c. Power stations are thought to be a
a. Oxygen has an atomic number of 8 and mass number 16. What is the electron structure of the oxygen atom?b. How many electrons, neutrons and protons are there in the oxygen atom?c. Oxygen molecules
The apparatus shown on Figure 11.6, was used to estimate the proportion of oxygen in the atmosphere. A volume of dry air (200 cm3) was passed backwards and forwards over heated copper until no
At room temperature and pressure (rtp), which of the substances listed below is:a. A solid element?b. A liquid element?c. A gaseous mixture?d. A solid mixture?e. A liquid compound?f. A solid
Explain the following.a. Hydroelectric power is a relatively cheap source of electricity.b. Geothermal energy is a non-polluting form of energy.c. A disadvantage of wind power is that it causes noise
One of the first practical chemical cells was the Daniell cell invented by John Daniell in 1836. A diagram of this type of cell is shown below.It is capable of generating about 1.1 volts and was used
Some nickel(ii) sulfate solution was carefully placed in the bottom of a beaker of water. The beaker was then covered and left for several days.a. Describe what you would see after:(i) A few
a. Draw diagrams to show the arrangement of particles in:(i) solid lead(ii) molten lead(iii) gaseous lead.b. Explain how the particles move in these three states of matter.c. Explain, using the
Explain the meaning of each of the following terms. In your answer include an example to help with your explanation.a. Expansion.b. Contraction.c. Physical change.d. Sublimation.e. Diffusion.f.
The following diagram shows the three states of matter and how they can be interchanged.a. Name the changes A to E.b. Name a substance which will undergo change E.c. Name a substance which will
a. Why do solids not diffuse?b. Give two examples of diffusion of gases and liquids found in the house.
Use the kinetic theory to explain the following: a. When you take a block of butter out of the fridge, it is quite hard. However, after 15 minutes it is soft enough to spread.b. When you come
The apparatus shown below was set up.Give explanations for the following observations.a. The formation of a white cloud.b. It took a few minutes before the white cloud formed.c. The white cloud
Define the following terms using specific examples to help with your explanation:a. Elementb. Metalc. Non-metald. Compounde. Moleculef. Mixtureg. Flocculationh. Geli. Foamj. Emulsionk. Sol.
Which of the substances listed below are: a. Metallic elements?b. Non-metallic elements?c. Compounds?d. Mixtures?Silicon, sea water, calcium, argon, water, air, carbon monoxide, iron, sodium
A student heated a mixture of iron filings and sulfur strongly. He saw a red glow spread through the mixture as the reaction continued. At the end of the experiment a black solid had been formed.a.
Name the method which is most suitable for separating the following:a. Oxygen from liquid airb. Red blood cells from plasmac. Petrol and kerosene from crude oild. Coffee grains from coffee solutione.
The table below shows the melting points, boiling points and densities of substances A to D.a. Which substance is a gas at room temperature?b. Which substance is a liquid at room temperature?c. Which
a. How many atoms of the different elements are there in the formulae of the compounds given below?(i) Nitric acid, HNO3(ii) Methane, CH4(iii) Copper nitrate, Cu(NO3)2(iv) Ethanoic acid, CH3COOH(v)
Carbon-fibre-reinforced plastic (CRP) is used in the manufacture of golf clubs and tennis rackets.a. What are composite materials?b. Which two substances are used to manufacture this composite
a. Define the terms: proton, neutron and electron.b. An atom X has a proton number of 19 and relative atomic mass of 39.(i) How many electrons, protons and neutrons are there in an atom of X?(ii) How
a. 6931Ga and 7131Ga are isotopes of gallium. With reference to this example, explain what you understand by the term isotope.b. A sample of gallium contains 60% of atoms of6931Ga and 40% of atoms of
Draw diagrams to show the bonding in each of the following compounds:a. Calcium fluoride (CaF2)b. Oxygen (O2)c. Magnesium chloride (MgCl2)d. Tetrachloromethane (CCl4).
The diagram shows the arrangement of the outer electrons only in a molecule of ethanoic acid.a. Name the different elements found in this compound.b. What is the total number of atoms present in this
Use the information given in Table 3.6 on p. 43 to work out the formula for:a. Silver oxideb. Zinc chloridec. Potassium sulfated. Calcium nitratee. Iron(ii) nitratef. Copper(ii) carbonateg. Iron(iii)
Atoms of elements X, Y and Z have 16, 17 and 19 electrons, respectively. Atoms of argon have 18 electrons.a. Determine the formulae of the compounds formed by the combination of the atoms of the
This is a diagram of an experiment in which electricity was passed through a mixture of distilled water containing a little dilute sulfuric acid.a. Name the gas that collects at A.b. Name the gas
The elements sodium and chlorine react together to form the compound sodium chloride, which has a giant ionic lattice structure. a. What type of structure do the elements(i) Sodium (ii)
Explain the following.a. Ammonia is a gas at room temperature.b. The melting points of sodium chloride and iodine are very different.c. Metals generally are good conductors of electricity.d.
Use the data in the table below to answer the questions which follow.Element ............ ArH ......................... 1C ........................ 12N ........................ 14O
Calculate the volume occupied, at rtp, by the following gases. (One mole of any gas occupies a volume of 24 dm3 at rtp.)a. 12.5 moles of sulfur dioxide gas.b. 0.15 mole of nitrogen gas.
Calculate the number of moles of gas present in the following:a. 36 cm3 of sulfur dioxideb. 144 dm3 of hydrogen sulfide.
Use the following experimental information to determine the empirical formula of an oxide of silicon.Mass of crucible ............................................... 18.20 gMass of crucible + silicon
a. Calculate the empirical formula of an organic liquid containing 26.67% of carbon and 2.22% of hydrogen, with the rest being oxygen.b. The Mr of the liquid is 90. What is its molecular formula?
Iron is extracted from its ore, haematite, in the blast furnace. The main extraction reaction is:Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)a. Name the reducing agent in this process.b. Name the oxide of
Consider the following information about the newly discovered element, vulcium, whose symbol is Vu. ‘Vulcium is a solid at room temperature. It is easily cut by a penknife to reveal a shiny surface
0.048 g of magnesium was reacted with excess dilute hydrochloric acid at room temperature and pressure. The hydrogen gas given off was collected.a. Write a word and balanced symbol equation for the
The apparatus shown in the diagram below was used to investigate the gases produced when a concentrated solution of potassium chloride was electrolysed.a. Name a non-metal suitable for use as
Explain the meaning of each of the following terms. Use a suitable example, in each case, to help with your explanation.a. Anode.b. Cathode.c. Electrolysis.d. Electrolyte.e. Anion.f. Cation.g.
Copper is purified by electrolysis, as in the example shown below.a. Name the materials used for the electrodes A and B.b. Name the electrolyte C and substance D.c. Why is substance D of economic
Copy and complete the table below, which shows the results of the electrolysis of four substances using inert electrodes.a. State what you understand by ‘inert electrodes’.b Explain why the
A pupil carried out an experiment in a fume cupboard to find out how electricity affected different substances. Some of the substances were in aqueous solution, others were in the molten state.
Sodium hydroxide is made by the electrolysis of brine.a. Draw and label a simplified diagram of the cell used in this process. Make certain that you have labelled on the diagram:(i) The
Electroplating is an important industrial process.a. Explain what electroplating is.b. Why are certain metals electroplated?c. Give two examples of the use of electroplating.
a. State which of the following processes is endothermic and which is exothermic.(i) The breaking of a chemical bond.(ii) The forming of a chemical bond.b. The table below shows the bond energy data
Crude oil is a mixture of hydrocarbons. The refining of crude oil produces fractions which are more useful to us than crude oil itself. Each fraction is composed of hydrocarbons which have boiling
The following results were obtained from an experiment carried out to measure the enthalpy of combustion (heat of combustion) of ethanol. The experiment involved heating a known volume of water with
Explain the following statements.a. A car exhaust pipe will rust much faster if the car is in constant use.b. Vegetables cook faster when they are chopped up.c. Industrial processes become more
This question is about endothermic and exothermic reactions.a. Explain the meaning of the terms endothermic and exothermic.b. (i) Draw an energy level diagram for the reaction:(ii) Is this reaction
The following results were obtained from a neutralisation reaction between 1 mol dm−3 hydrochloric acid and 1 mol dm−3 sodium hydroxide. This experiment was carried out to measure the heat of
Write down which factors are most important when deciding on a particular fuel for the purpose given:a. Fuel for a cigarette lighterb. Fuel for a camping stovec. Fuel for an aeroplaned. Fuel for an
A student performed two experiments to establish how effective manganese(iv) oxide was as a catalyst for the decomposition of hydrogen peroxide. The results below were obtained by carrying out these
‘Propagas’ is used in some central heating systems where natural gas is not available. It burns according to the following equation:a. What are the chemical names for ‘propagas’ and natural
a. Which of the following reaction mixtures ill produce hydrogen more quickly at room temperature?(i) Zinc granules + dilute nitric acid(ii) Zinc powder + dilute nitric acidb. Give an explanation of
A flask containing dilute hydrochloric acid was placed on a digital balance. An excess of limestone chippings was added to this acid, a plug of cotton wool was placed in the neck of the flask and the
a. What is a catalyst?b. List the properties of catalysts.c. Name the catalyst used in the following processes:(i) The Contact process(ii) The Haber process(iii) The hydrogenation of unsaturated
This question concerns the reaction of copper(ii) carbonate with dilute hydrochloric acid. The equation for the reaction is:CuCO3(s) + 2HCl(aq) → CuCl2(aq) + CO2(aq) + H2O(l)a. Sketch a graph to
European regulations state that all new cars have to be fitted with catalytic converters as part of their exhaust system.a. Why are these regulations necessary?b. Which gases are removed by catalytic
Suggest practical methods by which the rate of reaction can be investigated in each of the following cases:a. Magnesium reacting with hydrochloric acidb. Nitrogen monoxide reacting with oxygen.
Explain, with the aid of examples, what you understand by the following terms:a. Strong acidb. Weak acidc. Strong alkalid. Weak alkalie. Concentrated acid.

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