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24:[["$","$L33",null,{"feature":"flashcards"}],"$L34",["$","$L35",null,{"href":"/igcse/chemistry/cie/fuels/flashcards","label":"Fuels","subjectCode":"igcse_chemistry__cie","surface":"flashcards"}],["$","$L36",null,{"runner":["$","div",null,{"className":"min-h-0 flex-1 overflow-hidden bg-background","children":["$","$L37",null,{"decks":[{"id":"4b381a61-83e1-4743-8db8-538572124412","title":"Fuels Flashcards","topicId":"56fcb71f-019b-5784-a78d-0b14e2878a92","topicSlug":"fuels","cards":[{"id":"5a99fe47-f5fe-4b37-a689-25357914c2d0","cardType":"basic","points":2,"front":"In Chemistry, what does burning a fuel usually mean?","back":"Combustion: reaction with oxygen releasing heat energy.","mcqOptions":[{"text":"Combustion: reaction with oxygen releasing heat energy.","correct":true,"explanation":"Combustion is a chemical reaction in which a substance reacts with oxygen and transfers energy to the surroundings, mainly as heat."},{"text":"Thermal decomposition: breakdown by heating without oxygen.","correct":false,"explanation":"Thermal decomposition uses heat to break a compound into simpler substances and does not necessarily involve oxygen. Burning a fuel is combustion, which releases heat through reaction with oxygen."},{"text":"Neutralisation: reaction of acid with a base.","correct":false,"explanation":"Neutralisation is the reaction of an acid with a base, usually producing salt and water. Burning a fuel is combustion: reaction with oxygen that releases heat energy."},{"text":"Electrolysis: decomposition using electrical energy.","correct":false,"explanation":"Electrolysis uses electrical energy to decompose an ionic substance, rather than releasing heat by burning. Fuel burning is combustion, a reaction with oxygen."}]},{"id":"7573a589-bebe-47a1-960a-c421b98d96c3","cardType":"basic","points":3,"front":"Name the three fossil fuels in this topic.","back":"

Coal
Natural gas
Petroleum

","mcqOptions":[{"text":"

Coal
Natural gas
Petroleum

","correct":true,"explanation":"Coal, natural gas and petroleum formed from ancient organic material over millions of years, so they are the three fossil fuels studied in this topic."},{"text":"

Coal
Wood
Ethanol

","correct":false,"explanation":"Coal is a fossil fuel, but wood and ethanol are biofuels made from recently living material. The three fossil fuels are coal, natural gas and petroleum."},{"text":"

Natural gas
Hydrogen
Ethanol

","correct":false,"explanation":"Natural gas is a fossil fuel, whereas hydrogen and ethanol are not obtained as fossil fuels. The required three are coal, natural gas and petroleum."},{"text":"

Petroleum
Charcoal
Biogas

","correct":false,"explanation":"Petroleum is a fossil fuel, but charcoal is manufactured from wood and biogas comes from decomposing recent biomass. Coal, natural gas and petroleum are the three fossil fuels."}]},{"id":"5adf3524-12ae-432b-a24e-10e2408a98bf","cardType":"basic","points":2,"front":"Why are fossil fuels non-renewable?","back":"They are used much faster than they naturally form.","mcqOptions":[{"text":"They are used much faster than they naturally form.","correct":true,"explanation":"Fossil fuels take millions of years to form but are consumed rapidly. Their reserves therefore cannot be replaced at anything close to the rate of use."},{"text":"They are found much deeper than other natural resources.","correct":false,"explanation":"Difficulty of extraction does not determine whether a resource is renewable. Fossil fuels are non-renewable because they are used much faster than geological processes form them."},{"text":"They are stored much longer than other energy resources.","correct":false,"explanation":"Fossil fuels can be transported and stored, so this is not the reason for their classification. They are non-renewable because consumption greatly outpaces their natural formation."},{"text":"They are more polluting than naturally formed resources.","correct":false,"explanation":"Pollution is a disadvantage of fossil fuels, but it does not define non-renewability. They are non-renewable because they are used much faster than they naturally form."}]},{"id":"ac0beeaf-6853-4277-aa76-812331d99f3b","cardType":"cloze","points":null,"front":"The main constituent of natural gas is [ ], $CH_4$.","back":"The main constituent of natural gas is methane, $CH_4$.","mcqOptions":[{"text":"methane","correct":true,"explanation":"Methane has the molecular formula $CH_4$ and forms the largest proportion of natural gas, although small amounts of other hydrocarbons may also be present."},{"text":"ethane","correct":false,"explanation":"Ethane is a hydrocarbon that may occur in natural gas, but its formula is $C_2H_6$. The main constituent with formula $CH_4$ is methane."},{"text":"propane","correct":false,"explanation":"Propane may be obtained during natural-gas processing, but its formula is $C_3H_8$. Methane, $CH_4$, is the main constituent of natural gas."},{"text":"butane","correct":false,"explanation":"Butane is an alkane with formula $C_4H_{10}$ and is commonly used in bottled fuel. Natural gas consists mainly of methane, whose formula is $CH_4$."}]},{"id":"ce692af9-8c2d-4c07-a7cb-22a17c9ad5ef","cardType":"cloze","points":null,"front":"A hydrocarbon contains [ ] and [ ] only.","back":"A hydrocarbon contains carbon and hydrogen only.","mcqOptions":[{"text":"A hydrocarbon contains carbon and hydrogen only.","correct":true,"explanation":"By definition, a hydrocarbon is a compound whose only elements are carbon and hydrogen. Other elements may be present in fuels, but not within a hydrocarbon molecule."},{"text":"A hydrocarbon contains carbon and oxygen only.","correct":false,"explanation":"Replacing hydrogen with oxygen confuses hydrocarbons with oxygen-containing organic compounds. A hydrocarbon must contain carbon and hydrogen as its only elements."},{"text":"A hydrocarbon contains hydrogen and oxygen only.","correct":false,"explanation":"A compound containing hydrogen and oxygen only is not a hydrocarbon because it lacks carbon. Hydrocarbons contain carbon and hydrogen only."},{"text":"A hydrocarbon contains nitrogen and hydrogen only.","correct":false,"explanation":"Nitrogen can occur in some organic compounds, but it is not one of the two defining elements of hydrocarbons. Those elements are carbon and hydrogen only."}]},{"id":"bba12136-d0eb-456c-8492-4df065c7292c","cardType":"basic","points":1,"front":"Why is ethanol, $C_2H_5OH$, not a hydrocarbon?","back":"It contains oxygen.","mcqOptions":[{"text":"It contains oxygen.","correct":true,"explanation":"A hydrocarbon must contain carbon and hydrogen only. Ethanol also contains an oxygen atom in its $OH$ group, so it is not a hydrocarbon."},{"text":"It contains carbon.","correct":false,"explanation":"Containing carbon is necessary for a substance to be a hydrocarbon, not a reason to exclude it. Ethanol is excluded because it also contains oxygen."},{"text":"It contains hydrogen.","correct":false,"explanation":"Hydrogen is one of the two elements that every hydrocarbon contains. Ethanol is not a hydrocarbon because its formula shows oxygen as well as carbon and hydrogen."},{"text":"It contains nitrogen.","correct":false,"explanation":"Ethanol does not contain nitrogen, as its formula $C_2H_5OH$ confirms. It is not a hydrocarbon because the formula includes oxygen."}]},{"id":"148749bd-7c6d-49d0-ad7d-b108df79debd","cardType":"basic","points":2,"front":"Why is petroleum described as a mixture?","back":"It contains many different hydrocarbons, not one pure substance.","mcqOptions":[{"text":"It contains many different hydrocarbons, not one pure substance.","correct":true,"explanation":"Petroleum contains numerous hydrocarbon compounds with different molecular sizes and properties. It is therefore a mixture rather than a single pure chemical substance."},{"text":"It contains many different elements, not one pure substance.","correct":false,"explanation":"Different elements within one compound would not necessarily make a mixture. Petroleum is a mixture because it contains many distinct hydrocarbon compounds rather than one pure substance."},{"text":"It contains many separate atoms, not one pure substance.","correct":false,"explanation":"Hydrocarbons are compounds, not individual atoms, and petroleum contains molecules of many different hydrocarbons. This collection of different substances makes it a mixture."},{"text":"It contains many different states, not one pure substance.","correct":false,"explanation":"Physical states do not define whether a material is a mixture, and crude petroleum is predominantly liquid. It is a mixture because it contains many different hydrocarbons."}]},{"id":"a7e1b7d1-c150-441a-b0bd-346cca962534","cardType":"basic","points":1,"front":"What physical method separates petroleum into useful fractions?","back":"Fractional distillation.","mcqOptions":[{"text":"Fractional distillation.","correct":true,"explanation":"Fractional distillation separates petroleum because its hydrocarbons have different boiling points. They vaporise and condense at different temperatures within a fractionating column."},{"text":"Filtration.","correct":false,"explanation":"Filtration separates an insoluble solid from a fluid and cannot separate the dissolved liquid hydrocarbons in petroleum. Petroleum fractions are separated by fractional distillation."},{"text":"Crystallisation.","correct":false,"explanation":"Crystallisation obtains a dissolved solid by forming crystals, so it is unsuitable for petroleum’s mixture of liquids. Different boiling points allow fractional distillation to separate the fractions."},{"text":"Chromatography.","correct":false,"explanation":"Chromatography can separate small samples for analysis, but it is not the standard industrial method used to obtain petroleum fractions. Fractional distillation separates them by boiling point."}]},{"id":"d01ebf7f-6347-4b6f-b77f-331360e18602","cardType":"basic","points":2,"front":"Why can fractional distillation separate petroleum?","back":"The hydrocarbons have different boiling points.","mcqOptions":[{"text":"The hydrocarbons have different boiling points.","correct":true,"explanation":"Different hydrocarbons boil and condense at different temperatures, so they condense at different heights in the fractionating column and can be collected as separate fractions."},{"text":"The hydrocarbons have different melting points.","correct":false,"explanation":"Confusing melting with boiling overlooks the liquid-vapour changes used in fractional distillation. Separation is possible because the hydrocarbons have different boiling points."},{"text":"The hydrocarbons have different densities.","correct":false,"explanation":"Density differences can separate substances by settling, but that is not the basis of fractional distillation. Petroleum hydrocarbons are separated because they have different boiling points."},{"text":"The hydrocarbons have similar boiling points.","correct":false,"explanation":"Similar boiling points would make the hydrocarbons harder to separate because they would condense together. Fractional distillation works because their boiling points are different."}]},{"id":"37afdbbb-f62f-4964-8272-44dbfc2ffb20","cardType":"cloze","points":null,"front":"A petroleum fraction is collected over a particular [ ] during fractional distillation.","back":"A petroleum fraction is collected over a particular boiling-point range during fractional distillation.","mcqOptions":[{"text":"boiling-point range","correct":true,"explanation":"Each fraction contains several hydrocarbons with similar boiling points, so it is collected across a range of temperatures rather than at one precise temperature."},{"text":"melting-point range","correct":false,"explanation":"Melting points concern changes between solids and liquids, whereas fractional distillation involves vaporisation and condensation. A fraction is therefore collected over a boiling-point range."},{"text":"boiling-point value","correct":false,"explanation":"A single boiling-point value would suggest a pure substance. Each petroleum fraction is a mixture of hydrocarbons, so it is collected over a boiling-point range."},{"text":"molecular-mass range","correct":false,"explanation":"Although molecules within a fraction often have similar masses, the column separates them according to boiling behaviour. Collection therefore occurs over a boiling-point range."}]},{"id":"53431868-c240-44ba-b45a-7e71cbe1e3ae","cardType":"cloze","points":null,"front":"A fractionating column is [ ] and [ ].","back":"A fractionating column is hot at the bottom and cooler at the top.","mcqOptions":[{"text":"A fractionating column is hot at the bottom and cooler at the top.","correct":true,"explanation":"The column has a temperature gradient: strong heating keeps the bottom hot, while temperature decreases upwards, allowing different hydrocarbons to condense at different heights."},{"text":"A fractionating column is cool at the bottom and hotter at the top.","correct":false,"explanation":"This reverses the temperature gradient. The petroleum is heated at the base, so the column is hot at the bottom and cooler at the top."},{"text":"A fractionating column is hot at the bottom and hotter at the top.","correct":false,"explanation":"Temperature does not increase towards the top. Heating occurs at the base, making the column hot at the bottom and progressively cooler towards the top."},{"text":"A fractionating column is cool at the bottom and cooler at the top.","correct":false,"explanation":"Although the top is cooler, the bottom is not cool because petroleum is strongly heated there. The column is hot at the bottom and cooler at the top."}]},{"id":"7865a15f-43d2-4446-ab23-fcd4c87c7932","cardType":"basic","points":2,"front":"When does a hydrocarbon vapour condense in the fractionating column?","back":"When it reaches surroundings below its boiling point.","mcqOptions":[{"text":"When it reaches surroundings below its boiling point.","correct":true,"explanation":"Below its boiling point, the vapour loses enough energy for intermolecular attractions to hold its molecules together as a liquid, so condensation occurs."},{"text":"When it reaches surroundings above its boiling point.","correct":false,"explanation":"Above its boiling point, a hydrocarbon tends to remain a vapour rather than condense. It condenses when it reaches surroundings below its boiling point."},{"text":"When its molecules gain enough energy to escape.","correct":false,"explanation":"Gaining enough energy to escape describes vaporisation, the opposite change of state. Condensation happens when the vapour cools below its boiling point and loses energy."},{"text":"When it reaches the hottest part of the column.","correct":false,"explanation":"The hottest region keeps most hydrocarbons vaporised rather than causing condensation. A hydrocarbon condenses where the surroundings are below its boiling point."}]},{"id":"80360df5-b7b4-4bf6-a290-0263bc1b3b06","cardType":"basic","points":1,"front":"Does fractional distillation produce pure compounds from petroleum?","back":"No - it produces simpler mixtures of hydrocarbons.","mcqOptions":[{"text":"No - it produces simpler mixtures of hydrocarbons.","correct":true,"explanation":"Each fraction contains several hydrocarbons with similar boiling points, not one pure substance. Fractional distillation therefore separates petroleum into simpler mixtures."},{"text":"Yes - it produces pure hydrocarbons from petroleum.","correct":false,"explanation":"Treating each fraction as a pure hydrocarbon ignores its boiling-point range. Every fraction contains a mixture of hydrocarbons with similar boiling points."},{"text":"No - it produces simpler elements from hydrocarbons.","correct":false,"explanation":"Fractional distillation is a physical separation and does not decompose compounds into elements. It produces simpler mixtures of hydrocarbons with similar boiling points."},{"text":"Yes - it produces new compounds by chemical reaction.","correct":false,"explanation":"No chemical reaction occurs during fractional distillation, so no new compounds form. The process physically separates petroleum into simpler mixtures of hydrocarbons."}]},{"id":"60e06bdb-bb50-404a-a69f-eccd7cae74c2","cardType":"basic","points":2,"front":"Why do larger hydrocarbon molecules usually have higher boiling points?","back":"They have stronger attractions between molecules.","mcqOptions":[{"text":"They have stronger attractions between molecules.","correct":true,"explanation":"Larger hydrocarbon molecules have stronger intermolecular attractions because they contain more electrons and have greater surface contact. More energy is therefore needed to separate them."},{"text":"They have weaker attractions between molecules.","correct":false,"explanation":"Weaker intermolecular attractions would require less energy to overcome and would lower the boiling point. Larger hydrocarbons instead have stronger attractions between their molecules."},{"text":"They have stronger covalent bonds within molecules.","correct":false,"explanation":"Boiling does not break the covalent bonds within hydrocarbon molecules. It overcomes intermolecular attractions, which are stronger for larger hydrocarbon molecules."},{"text":"They have more energy stored in molecules.","correct":false,"explanation":"Boiling point depends on the energy required to overcome intermolecular attractions, not stored chemical energy. Larger molecules have stronger attractions between them."}]},{"id":"eec6a4ca-18c4-4a74-887c-dea5df340073","cardType":"cloze","points":null,"front":"Going up the fractionating column, chain length [ ] and boiling point [ ].","back":"Going up the fractionating column, chain length decreases and boiling point decreases.","mcqOptions":[{"text":"Going up the fractionating column, chain length decreases and boiling point decreases.","correct":true,"explanation":"Shorter-chain hydrocarbons have weaker intermolecular attractions and lower boiling points, so they remain gaseous for longer and rise higher before condensing."},{"text":"Going up the fractionating column, chain length increases and boiling point decreases.","correct":false,"explanation":"This separates two linked trends incorrectly. Longer chains generally have stronger intermolecular attractions and higher boiling points; both chain length and boiling point decrease upwards."},{"text":"Going up the fractionating column, chain length decreases and boiling point increases.","correct":false,"explanation":"Shorter chains do not generally have higher boiling points; their weaker intermolecular attractions give lower boiling points. Both chain length and boiling point decrease upwards."},{"text":"Going up the fractionating column, chain length increases and boiling point increases.","correct":false,"explanation":"This reverses both trends. Long-chain, high-boiling hydrocarbons condense near the hot bottom, while short-chain, low-boiling hydrocarbons rise towards the top."}]},{"id":"ea98c457-2664-4ef8-ab67-2407f867afdd","cardType":"cloze","points":null,"front":"Going up the fractionating column, fractions become more [ ] and [ ].","back":"Going up the fractionating column, fractions become more volatile and less viscous.","mcqOptions":[{"text":"Going up the fractionating column, fractions become more volatile and less viscous.","correct":true,"explanation":"Fractions higher in the column contain shorter-chain hydrocarbons with lower boiling points. They evaporate more readily and flow more easily, making them more volatile and less viscous."},{"text":"Going up the fractionating column, fractions become more volatile and more viscous.","correct":false,"explanation":"Higher fractions are more volatile, but their shorter molecules slide past one another more easily. They are therefore less viscous, not more viscous."},{"text":"Going up the fractionating column, fractions become more less volatile and less viscous.","correct":false,"explanation":"The viscosity trend is correct, but volatility is reversed. Shorter-chain fractions have lower boiling points and evaporate more easily, so they are more volatile."},{"text":"Going up the fractionating column, fractions become more less volatile and more viscous.","correct":false,"explanation":"This describes the heavy fractions found near the bottom of the column. Fractions become more volatile and less viscous as chain length decreases upwards."}]},{"id":"15cc830f-0812-4329-8132-68e62bb59711","cardType":"basic","points":1,"front":"Which petroleum fraction is used as gas for heating and cooking?","back":"The refinery gas fraction.","mcqOptions":[{"text":"The refinery gas fraction.","correct":true,"explanation":"Refinery gas contains small hydrocarbons that are gases at room temperature. It is supplied as a convenient fuel for heating and cooking."},{"text":"The gasoline/petrol fraction.","correct":false,"explanation":"Gasoline/petrol is a volatile liquid used mainly as fuel in cars, not as a domestic gas. Refinery gas is used for heating and cooking."},{"text":"The kerosene/paraffin fraction.","correct":false,"explanation":"Kerosene/paraffin is a liquid fraction used mainly as jet fuel. Refinery gas contains gaseous hydrocarbons and is the fraction used for heating and cooking."},{"text":"The fuel oil fraction.","correct":false,"explanation":"Fuel oil is a heavy liquid fraction used in ships and some heating systems, not as cooking gas. The gaseous fraction used domestically is refinery gas."}]},{"id":"d3da6252-2bdf-4567-8234-ceed2d9fe608","cardType":"basic","points":1,"front":"Which petroleum fraction is used as fuel in cars?","back":"The gasoline/petrol fraction.","mcqOptions":[{"text":"The gasoline/petrol fraction.","correct":true,"explanation":"Gasoline, also called petrol, contains hydrocarbons with suitable volatility and combustion properties for use as fuel in petrol-engine cars."},{"text":"The naphtha fraction.","correct":false,"explanation":"Naphtha is primarily used as a chemical feedstock rather than directly as car fuel. Gasoline/petrol is the fraction used in petrol-engine cars."},{"text":"The kerosene/paraffin fraction.","correct":false,"explanation":"Kerosene/paraffin is often confused with petrol because both are fuels, but kerosene is mainly jet fuel. Gasoline/petrol is used in petrol-engine cars."},{"text":"The fuel oil fraction.","correct":false,"explanation":"Fuel oil is too heavy and insufficiently volatile for petrol-engine cars; it is mainly used in ships and heating systems. Cars use the gasoline/petrol fraction."}]},{"id":"c5e7a05e-3894-43b2-a2ca-804eeb476095","cardType":"basic","points":1,"front":"Which petroleum fraction is used as a chemical feedstock?","back":"The naphtha fraction.","mcqOptions":[{"text":"The naphtha fraction.","correct":true,"explanation":"Naphtha is used as a chemical feedstock, providing hydrocarbon raw materials that can be processed into useful chemicals and polymers."},{"text":"The refinery gas fraction.","correct":false,"explanation":"Refinery gas is mainly burned for heating and cooking rather than used as the standard chemical feedstock fraction. That role belongs to naphtha."},{"text":"The gasoline/petrol fraction.","correct":false,"explanation":"Gasoline/petrol is chiefly blended and burned as car fuel, not identified as the main chemical feedstock. Naphtha supplies raw materials for chemical manufacture."},{"text":"The lubricating oil fraction.","correct":false,"explanation":"Lubricating oil is used to make lubricants, waxes and polishes rather than as a chemical feedstock. The petroleum fraction used as feedstock is naphtha."}]},{"id":"d6c9f4ed-735d-41c0-b58f-054300691e5c","cardType":"basic","points":1,"front":"Which petroleum fraction is used as jet fuel?","back":"The kerosene/paraffin fraction.","mcqOptions":[{"text":"The kerosene/paraffin fraction.","correct":true,"explanation":"Kerosene, also called paraffin, has suitable volatility and combustion characteristics for use as fuel in jet aircraft engines."},{"text":"The gasoline/petrol fraction.","correct":false,"explanation":"Gasoline/petrol is more volatile and is mainly used in car engines, not as standard jet fuel. Jets use the kerosene/paraffin fraction."},{"text":"The diesel oil/gas oil fraction.","correct":false,"explanation":"Diesel oil/gas oil is designed for compression-ignition diesel engines, which can make it seem plausible. Jet aircraft normally use the kerosene/paraffin fraction."},{"text":"The fuel oil fraction.","correct":false,"explanation":"Fuel oil is a heavier, less volatile fraction used mainly in ships and heating systems. Jet engines require the lighter kerosene/paraffin fraction."}]},{"id":"a80025df-350c-4777-9c14-86ef573b3740","cardType":"basic","points":1,"front":"Which petroleum fraction is used in diesel engines?","back":"The diesel oil/gas oil fraction.","mcqOptions":[{"text":"The diesel oil/gas oil fraction.","correct":true,"explanation":"Diesel oil, also called gas oil, has properties suited to ignition under compression, so it is used as fuel in diesel engines."},{"text":"The gasoline/petrol fraction.","correct":false,"explanation":"Gasoline/petrol is used in spark-ignition petrol engines, not diesel engines. Compression-ignition diesel engines use the diesel oil/gas oil fraction."},{"text":"The kerosene/paraffin fraction.","correct":false,"explanation":"Kerosene/paraffin is a middle fraction like diesel, making it a tempting confusion, but its main use is jet fuel. Diesel engines use diesel oil/gas oil."},{"text":"The lubricating oil fraction.","correct":false,"explanation":"Lubricating oil reduces friction in engines but is not burned as their fuel. Diesel engines are fuelled by the diesel oil/gas oil fraction."}]},{"id":"b6937e89-b732-4fb9-a721-7d6f67d70bde","cardType":"basic","points":1,"front":"Which petroleum fraction is used in ships and home heating systems?","back":"The fuel oil fraction.","mcqOptions":[{"text":"The fuel oil fraction.","correct":true,"explanation":"Fuel oil is a heavy petroleum fraction that releases energy when burned, making it suitable for ships and large domestic heating systems."},{"text":"The naphtha fraction.","correct":false,"explanation":"Naphtha is mainly used as a feedstock for manufacturing chemicals, not as a heavy fuel for ships and heating systems. Fuel oil serves those uses."},{"text":"The lubricating oil fraction.","correct":false,"explanation":"Lubricating oil is used for lubrication and for making waxes and polishes, rather than burned in ships and heating systems. The correct fraction is fuel oil."},{"text":"The bitumen fraction.","correct":false,"explanation":"Bitumen is the thick residue used for road surfacing and is not normally burned as ship or heating fuel. Those applications use fuel oil."}]},{"id":"41173b5c-034c-459b-9115-4e850dd59ba8","cardType":"basic","points":1,"front":"Which petroleum fraction is used for lubricants, waxes and polishes?","back":"The lubricating oil fraction.","mcqOptions":[{"text":"The lubricating oil fraction.","correct":true,"explanation":"Lubricating oil contains long-chain hydrocarbons with suitable viscosity and low volatility, allowing it to make lubricants, waxes and polishes."},{"text":"The naphtha fraction.","correct":false,"explanation":"Naphtha is a lighter fraction used as a chemical feedstock, not for lubricants, waxes and polishes. These products come from the lubricating oil fraction."},{"text":"The fuel oil fraction.","correct":false,"explanation":"Fuel oil is a heavy fraction, which may make it seem suitable, but it is mainly burned in ships and heating systems. Lubricating oil makes these products."},{"text":"The bitumen fraction.","correct":false,"explanation":"Bitumen is the very thick residue used primarily for road surfacing, not for making lubricants, waxes and polishes. These uses belong to lubricating oil."}]},{"id":"70d74bbb-9c92-4994-b748-cefbc70a5f87","cardType":"basic","points":1,"front":"Which petroleum fraction is used for making roads?","back":"The bitumen fraction.","mcqOptions":[{"text":"The bitumen fraction.","correct":true,"explanation":"Bitumen is the thick, high-boiling residue from fractional distillation. Its durable and waterproof properties make it suitable for binding and surfacing roads."},{"text":"The fuel oil fraction.","correct":false,"explanation":"Fuel oil is heavy and viscous, which makes it a plausible confusion, but it is burned in ships and heating systems. Roads are made using bitumen."},{"text":"The lubricating oil fraction.","correct":false,"explanation":"Lubricating oil is used for lubricants, waxes and polishes rather than road surfacing. The thick residual fraction used for making roads is bitumen."},{"text":"The naphtha fraction.","correct":false,"explanation":"Naphtha is a relatively light fraction used as a chemical feedstock, so it lacks the thick consistency needed for roads. Road surfacing uses bitumen."}]}]}],"examCountdown":null,"heading":"Fuels","title":"Fuels Flashcards","topbar":{"backHref":"/igcse/chemistry/cie/flashcards"},"topicSidebar":"$L38"}]}],"topicId":"56fcb71f-019b-5784-a78d-0b14e2878a92","walled":"$L39"}],"$L3a","$L3b"]