Hydrocarbons contain the elements... and... only. (1) H 6. Draw a ring around the correct answer to complete the sentence.

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1 Q. Alkanes are hydrocarbons found in crude oil. (a) (i) Complete the sentence. Hydrocarbons contain the elements... and... only. () Ethane is an alkane with the formula C H 6 Draw a ring around the correct answer to complete the sentence. C n H n Alkanes are hydrocarbons with the general formula C n H n C n H n+ () (b) Crude oil is separated into useful fractions by fractional distillation. Describe and explain how crude oil is separated into fractions by fractional distillation. Use the diagram to help you answer the question. (4) Page of 0

2 (c) Dodecane (C H 6 ) from crude oil is cracked to produce ethene (C H 4 ). (i) Complete the equation for this reaction. C H 6 C H () Give two conditions needed for cracking () (Total 9 marks) Q. This question is about compounds produced from crude oil. The table below shows four of these compounds. Compound Melting point in C Boiling point in C methane (CH 4 ) ethene (C H 4 ) decane (C 0 H ) icosane (C 0 H 4 ) (a) Tick ( ) two correct statements about the four compounds. Statement Tick ( ) Methane has the lowest melting point and icosane has the highest boiling point. Ethene and methane are alkanes. Methane and decane are gases at room temperature (0 C). Decane and icosane are liquid at 00 C. () (b) Petrol contains a mixture of compounds, including octane (C 8 H 8 ). Complete the word equation for the complete combustion of octane. octane + oxygen () Page of 0

3 (c) Most petrol used in cars contains about 5% ethanol (C H 5 OH). Ethanol can be produced from sugar cane. (i) Draw a ring around the correct answer to complete the sentence. combustion. The reaction to produce ethanol from sugar solution is displacement. fermentation. () Some people say that increasing the production of ethanol from sugar cane will be good for the environment. Suggest two reasons why () Page 3 of 0

4 (iii) Other people say that increasing the production of ethanol from sugar cane will be bad for the environment. Suggest two reasons why () (Total 9 marks) Q3. Petrol is a hydrocarbon fuel. (a) Complete this sentence. Hydrocarbons are compounds which are made from the elements... and... only. () (b) This apparatus was used to study the combustion of a hydrocarbon fuel. (i) Name the substance which changed the anhydrous copper sulphate from white to blue. () Page 4 of 0

5 Carbon dioxide is also produced when the hydrocarbon fuel is burned. Name the solution, labelled X on the diagram, which tests for carbon dioxide. () (iii) Complete this sentence. Carbon dioxide turns solution X... () (c) The graph shows how the concentration of carbon dioxide in the air has varied since the year 000. (i) Describe the changes in the concentration of carbon dioxide in the air since the year 000. (3) Suggest why the concentration of carbon dioxide in the air has changed since the year 800. () (Total 9 marks) Page 5 of 0

6 Q4. The structural formulae of two saturated hydrocarbons are shown below. Describe two ways in which they will differ in their physical properties (Total marks) Page 6 of 0

7 C n H n+ M. (a) (i) hydrogen / H and carbon / C answers can be in either order if letters given, must be capital H (b) (most) crude oil vaporises / evaporates or crude oil enters as a vapour (vapour) cools as it rises up the tower / column or tower / column cooler at the top or negative temperature gradient the fractions have different boiling / condensation points / ranges accept the larger the molecules, the higher the boiling point / condensation point so they will condense at different levels in the tower allow will collect at different levels if condensation mentioned allow will condense to give different fractions if no other mark is gained allow mark for mention of heating (c) (i) C 8 H 8 if one answer is given C8 H8 is the only acceptable answer credit any correct combination of alkanes and alkenes, eg C 5 H and C 3 H 6 hot / high temperature accept any temperature in the range C heat is insufficient catalyst accept a named catalyst alumina or zeolites or aluminosilicates or broken pot ignore other named catalysts allow (mixing with) steam as an alternative to second marking point ignore pressure [9] M. (a) Methane has the lowest melting point and icosane has the highest boiling point Decane and icosane are liquid at 00 C Page 7 of 0

8 (b) water / H O either order carbon dioxide / CO allow hydrogen oxide (c) (i) fermentation any two from: sugar cane / plants absorb carbon dioxide ignore oxygen released growing sugar cane / plants reduces global warming allow ethanol from plants is carbon neutral renewable resource / sustainable accept conserves fossil fuels / petrol (iii) any two from: destruction of habitats / forests (to grow sugar cane/crops) fermentation releases carbon dioxide production plants cause visual pollution pollution from the transportation of sugar cane / Ethanol growing sugar cane / plants uses a lot of land [9] M3. (a) hydrogen accept correct symbols but not H carbon (b) (i) water accept limewater / calcium hydroxide accept Ca(OH) (iii) milky / cloudy / chalky / white Page 8 of 0

9 (c) (i) remains almost the same / increases then decreases slightly from 000 to 800 increases / rises after 800 rapidly (owtte) increased burning of hydrocarbon / (fossil) fuels, etc. or increased use of fuels accept deforestation accept (more) cars / lorries / planes etc. accept power stations do not accept just factories [9] M4. B will have higher melting point higher boiling point be less volatile be more viscous (allow less flammable) any two for mark each [] Page 9 of 0

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