CIE iGCSE Co-Ordinated Science C11.3 Fuels Exam Style Questions Paper 3
Question
(a) Petroleum is separated into different fractions.
Table 8.1 shows the percentage composition of a 500kg sample of petroleum.
(i) Identify fraction X.
…………………………………………………………………………………………………………………….
(ii) Most of the fractions are used as fuels.
State one other use for the naphtha fraction.
…………………………………………………………………………………………………………………….
(iii) State the name of the process used to separate petroleum into different fractions.
…………………………………………………………………………………………………………………….
(iv) Calculate the mass of diesel oil obtained from the 500kg sample of petroleum.
mass of diesel oil = …………………………………………….. kg
(v) State the two chemical elements present in the molecules of the fractions in Table 8.1.
……………………………………………………… and ………………………………………………………
(b) (i) Petroleum is a fossil fuel.
State the name of one other fossil fuel.
…………………………………………………………………………………………………………………….
(ii) When fossil fuels are burned, carbon dioxide is made.
Carbon dioxide is a greenhouse gas.
State the name of one other greenhouse gas.
…………………………………………………………………………………………………………………….
(iii) Burning fossil fuels is a chemical change.
State two differences between a chemical change and a physical change.
1 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans : 8(a)(i) refinery gas ;
8(a)(ii) feedstock for making chemicals ;
8(a)(iii) fractional distillation ;
8(a)(iv) 130 (kg) ;
8(a)(v) carbon ;
hydrogen ;
8(b)(i) coal / natural gas ;
8(b)(ii) methane ;
8(b)(iii) chemical change cannot be reversed by physical means / easily ;
chemical change new substances are formed ;
Question
(a) Five different energy sources are shown in the list.
coal geothermal hydroelectric nuclear solar
(i) Circle the energy source in the list that produces carbon dioxide when it is used to generate electricity in a power station.
(ii) State the name of one renewable energy source not shown in the list.
(iii) State the form of energy stored in coal.
(iv) Suggest one advantage and one disadvantage of solar power compared to nuclear
power.
advantage ………………………………………………………………………………………………………….
disadvantage ………………………………………………………………………………………………………
(b) In a nuclear power station, there are radioactive materials. Emissions from these materials
include α-particles, β-particles and γ-rays.
(i) State the emission which is part of the electromagnetic spectrum.
(ii) Write the name of this emission in the correct position in the incomplete electromagnetic
spectrum in Fig. 6.1.
(iii) Place α-particles, β-particles and γ-rays in order of their penetrating abilities.
greatest penetration …………………………………………………………
least penetration …………………………………………………………
(iv) Describe the nature of an α-particle.
(c) The nuclear fuel used in some power stations is plutonium-239.
Plutonium-239 decays by α-particle emission to produce uranium-235.
Plutonium-239 has a half-life of 24000 years.
(i) 100g of plutonium-239 is sealed in a lead container and left for 96000 years.
Calculate the mass of plutonium-239 remaining after 96000 years.
mass = ………………………………………………g
(ii) Complete the word equation to show the decay of a nucleus of plutonium-239.
plutonium-239→ ………………………………… + …………………………………
▶Answer/Explanation
Ans: 6(a)(iii) chemical (potential) ;
6(a)(iv) advantage – no nuclear waste / no nuclear accidents;
disadvantage – only available during the day;
6(b)(i) γ- rays ;
6(b)(ii) left hand box ;
6(b)(iii) γ- rays
β- particles
α- particles ;
6(b)(iv) helium nucleus / 2 protons and 2 neutrons ;
6(c)(i) four half lives ;
6.25 (g) ;
6(c)(ii) plutonium – 239 → uranium – 235 + α (particle) ;
Question
(a) Fig. 8.1 shows the separation of petroleum into useful fractions.
Only two fractions are shown.
(i) Petroleum is a fossil fuel.
State the name of one other fossil fuel.
(ii) State the name of the process shown in Fig. 8.1.
(iii) State the name of one fraction not shown in Fig. 8.1.
(iv) State one use for each of the fractions shown in Fig. 8.1.
refinery gas ……………………………………………………………………………..
diesel oil …………………………………………………………………………………..
(b) Cracking is a process that produces small alkene molecules from larger alkane molecules.
Ethane is an alkane.
Ethene is an alkene.
Fig. 8.2 shows the structure of ethane, C2H6.
Draw the structure of ethene, C2H4.
(c) Ethene is used to make a polymer.
(i) State the name of the polymer that is made from ethene.
(ii) State the type of polymerisation reaction that makes this polymer from ethene.
▶️Answer/Explanation
Ans : 8(a)(i) coal / natural gas ;
8(a)(ii) fractional distillation ;
8(a)(iii) gasoline / naphtha / bitumen ;
8(a)(iv) (bottled gas for) heating and cooking ;
fuel for diesel engines ;
8(b) 
carbon carbon double bond ;
all else correct ;
8(c)(i) poly(ethene) ;
8(c)(ii) addition (polymerisation) ;
Question
(a) Petroleum is a fossil fuel.
State the name of one other fossil fuel. (Sub-topic – C11.3)
▶️Answer/Explanation
Coal / natural gas
(b) Petroleum is separated into useful fractions by fractional distillation.
State why fractional distillation is a physical change and not a chemical change. (Sub-topic – C6.1)
▶️Answer/Explanation
Change is reversible / no new products formed
(c) The fractions obtained from petroleum have different uses.
On Fig. 2.1, draw one line from each fraction to its use. One line has been drawn for you. (Sub-topic – C11.3)
| Fraction | Use |
|---|---|
| Bitumen | Road surfaces |
| Gas oil | Diesel engine fuel |
| Gasoline | Petrol engine fuel |
▶️Answer/Explanation
Bitumen – road surfaces; Gas oil – diesel engine fuel; Gasoline – petrol engine fuel
(d) Ethane and ethene are both found in petroleum. Ethane, \( C_2H_6 \), is an alkane. Ethene, \( C_2H_4 \), is an alkene. (Sub-topic – C11.5)
(i) Explain why ethene is described as being unsaturated.
▶️Answer/Explanation
Contains a carbon-carbon double bond
(ii) State the chemical test used to distinguish between an alkane and an alkene.
Describe the observation for an alkane and for an alkene.
▶️Answer/Explanation
Test: Aqueous bromine
Observation for alkane: No change / stays orange
Observation for alkene: Decolourises
(iii) State the total number of atoms in one molecule of ethene, \( C_2H_4 \).
▶️Answer/Explanation
Six
(iv) Complete Fig. 2.2 to show the structural formula of ethane, \( C_2H_6 \).
▶️Answer/Explanation
H
H-C-C-H
H
(v) Ethene molecules react together when heated to make a polymer.
State the name of the polymer made from ethene.
▶️Answer/Explanation
Polyethene / polythene
Question
Petroleum is a raw material for the production of useful substances.
Fig. 8.1 shows three processes, X, Y and Z, used to make ethanol.
(a) Identify process X and process Y.
process X ………………………………………………………………………………………………………………….
process Y ………………………………………………………………………………………………………………….
(b) State the substance added to ethene during process Z to make ethanol.
…………………………………………………………………………………………………………………………………
(c) Ethene is a hydrocarbon.
Explain why ethene is described as a hydrocarbon.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
(d) State the two products of the complete combustion of ethene.
1 ………………………………………………………………………………………………………………………………
2 ………………………………………………………………………………………………………………………………
(e) Complete Fig. 8.2 to show the structure of an ethanol molecule, C2H5OH. Include all the atoms and bonds.
Fig. 8.2
▶️Answer/Explanation
Ans: 8(a) process X – fractional distillation ;
process Y – cracking ;
8(b) steam ;
8(c) contains carbon and hydrogen (atoms) ;
only ;
8(d) carbon dioxide ;
water ;
8(e)
O – H attached to carbon ;
all else correct ;
Question
2. (a) (i) State what is meant by the term hydrocarbon.
▶️Answer/Explanation
Answer: contains carbon and hydrogen (atoms); only
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: A hydrocarbon is a compound that contains only carbon and hydrogen atoms.
2. (a) (ii) State the fossil fuel whose main constituent is methane.
▶️Answer/Explanation
Answer: natural gas
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The fossil fuel whose main constituent is methane is natural gas.
2. (b) Complete the dot-and-cross diagram of a molecule of methane in Fig. 2.1. Include the symbols for the chemical elements. Show outer shell electrons only.
▶️Answer/Explanation
Answer: correct symbols; 4 bonding pairs and all else correct
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The dot-and-cross diagram for methane (CH₄) should show one carbon atom with four hydrogen atoms, each sharing one electron with the carbon atom. The carbon atom has four outer shell electrons, and each hydrogen atom has one outer shell electron.
2. (c) (i) The combustion of methane is an exothermic reaction. State what is meant by exothermic.
▶️Answer/Explanation
Answer: gives out (thermal) energy
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: An exothermic reaction is a chemical reaction that releases energy in the form of heat or light.
2. (c) (ii) State the two products of the complete combustion of methane in oxygen.
▶️Answer/Explanation
Answer: carbon dioxide; water
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The complete combustion of methane in oxygen produces carbon dioxide (CO₂) and water (H₂O).
2. (c) (iii) During the incomplete combustion of methane, carbon monoxide is sometimes made. Describe one adverse effect of carbon monoxide on the health of humans.
▶️Answer/Explanation
Answer: death / poisoning / CO is toxic / reduces the oxygen carrying capacity of the red blood cells
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: Carbon monoxide is toxic and can bind to hemoglobin in red blood cells, reducing their ability to carry oxygen, which can lead to poisoning or death.
2. (d) (i) State the difference in structure between an alkane and an alkene.
▶️Answer/Explanation
Answer: alkene contains a double bond / alkane only has single bonds
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The main difference between an alkane and an alkene is that alkenes contain at least one carbon-carbon double bond, while alkanes contain only single bonds.
2. (d) (ii) Describe a chemical test that distinguishes between an alkane and an alkene. Describe the observations for a positive result of the test in each case.
▶️Answer/Explanation
Answer: aqueous bromine; alkane – no colour change; alkene – orange to colourless / goes colourless
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: A chemical test to distinguish between an alkane and an alkene is the bromine water test. Alkanes do not react with bromine water, so there is no color change. Alkenes react with bromine water, causing the orange color to disappear, indicating the presence of a double bond.
Question(a)
Petroleum is a fossil fuel.
(i) Name one other fossil fuel.
(ii) Petroleum is separated into fractions to make it more useful. Complete the sentences using words from the list.
List: compound, distillation, electrolysis, filtration, mixture, molecule
Petroleum is a …… of different hydrocarbons. Petroleum is separated by fractional …….
(iii) Gasoline is obtained from petroleum. State the two products of the complete combustion of gasoline.
▶️Answer/Explanation
(i) Another fossil fuel is coal or natural gas.
(ii) The completed sentences are:
- Petroleum is a mixture of different hydrocarbons.
- Petroleum is separated by fractional distillation.
(iii) The two products of the complete combustion of gasoline are:
- Carbon dioxide (CO2)
- Water (H2O)
Detailed Solution:
(i) Fossil fuels are formed from the remains of ancient plants and animals. Examples include coal, natural gas, and petroleum.
(ii) Petroleum is a complex mixture of hydrocarbons. Fractional distillation is the process used to separate these hydrocarbons based on their boiling points. This process occurs in a fractionating column, where different fractions (e.g., gasoline, diesel) are collected at different heights.
(iii) Complete combustion of gasoline (a hydrocarbon) occurs in the presence of sufficient oxygen. The products are carbon dioxide (CO2) and water (H2O), as the hydrocarbon reacts with oxygen to form these compounds.
Question(b)
Ethane, C2H6, is an alkane. Ethene, C2H4, is an alkene.
(i) Explain why ethene is described as an unsaturated hydrocarbon.
(ii) Describe the chemical test and the positive result for an unsaturated hydrocarbon.
▶️Answer/Explanation
(i) Ethene is described as an unsaturated hydrocarbon because it contains a carbon-carbon double bond, which allows it to undergo addition reactions.
(ii) The chemical test for an unsaturated hydrocarbon is:
- Test: Add aqueous bromine (bromine water) to the hydrocarbon.
- Positive Result: The bromine water changes from orange/brown to colorless.
Detailed Solution:
(i) Unsaturated hydrocarbons contain at least one carbon-carbon double or triple bond. Ethene (C2H4) has a double bond between the two carbon atoms, making it unsaturated. This double bond allows ethene to react with other substances in addition reactions.
(ii) The bromine water test is used to identify unsaturated hydrocarbons. When bromine water is added to an unsaturated hydrocarbon, the double bond reacts with the bromine, causing the orange/brown color of bromine to disappear. This indicates the presence of an unsaturated hydrocarbon.
Question(c)
Ethene molecules react together to form a polymer.
(i) Describe what happens to the ethene molecules when they form a polymer.
(ii) Name the polymer made from ethene.
▶️Answer/Explanation
(i) When ethene molecules form a polymer, they join together in long chains through a process called addition polymerization. The double bonds in ethene break, and the molecules link together to form a polymer.
(ii) The polymer made from ethene is polyethene (also called polyethylene).
Detailed Solution:
(i) In addition polymerization, the double bonds in ethene molecules break, and the carbon atoms form single bonds with other ethene molecules. This creates a long chain of repeating units, known as a polymer.
(ii) The polymer formed from ethene is called polyethene (or polyethylene). It is a widely used plastic in packaging, containers, and other applications due to its durability and flexibility.
Question
(a) Petroleum is separated into useful fractions by fractional distillation. (Sub-topic – C11.3)
Fig. 5.1 shows a simplified diagram for the fractional distillation of petroleum.
(i) On Fig. 5.1 write the names of the missing fractions in their correct place.
▶️Answer/Explanation
Answer:
The missing fractions are:
1. Gasoline
2. Bitumen
(ii) State one use for the refinery gas fraction.
▶️Answer/Explanation
Answer:
Used as fuel for heating and cooking.
(iii) State why the process of fractional distillation is a physical change and not a chemical change.
▶️Answer/Explanation
Answer:
No new substances are formed during fractional distillation; it only involves the separation of different components based on their boiling points.
(b) The diesel oil fraction is used as a fuel. (Sub-topic – C11.3)
(i) Diesel oil is a mixture of hydrocarbons.
State what is meant by the term hydrocarbon.
▶️Answer/Explanation
Answer:
substance that contains carbon and hydrogen (atoms) ;
only ;
(ii) State the two products of the complete combustion of a hydrocarbon.
▶️Answer/Explanation
Answer:
1. Carbon dioxide
2. Water
(c) Sub-topic – C11.5
(i) Name the process that produces small alkene molecules from larger alkane molecules.
▶️Answer/Explanation
Answer:
Cracking
(ii) State how the molecular structure of an alkane molecule differs from the molecular structure of an alkene molecule.
▶️Answer/Explanation
Answer:
alkane does not contain a C-C double bond / alkene does contain a C-C double bond / contains only single bonds ;
(iii) Aqueous bromine is used to test for an alkene.
State the colour change when aqueous bromine reacts with an alkene.
from ……………………………………………. to …………………………………………….
▶️Answer/Explanation
Answer:
From orange to colourless.