Question
Petroleum is a useful natural resource.
The diagram shows how petroleum can be separated into useful substances.
(a) What is the name of the separation process shown in the diagram?
(b) Name the fraction leaving at:
A ………………………………………………………………………………………………………………………………
B ………………………………………………………………………………………………………………………………
(c) Refinery gas is a mixture of hydrocarbons.
One refinery gas is butane, \(C_4H_{10}\).
(i) Suggest the names of two other refinery gases.
……………………………………………………… and ……………………………………………………..
(ii) Write the chemical equation for the complete combustion of butane.
(iii) Name the toxic gas produced by the incomplete combustion of butane.
(d) Gasoline and kerosene are both fuels. They have different properties.
(i) Describe the differences in the properties given.
viscosity of the fuel ……………………………………………………………………………………………….
flammability of the fuel …………………………………………………………………………………………..
(ii) What difference in the molecules of gasoline and kerosene causes these differences in
properties?
(e) Hydrogen fuel cells can be used to power vehicles.
Write the word equation for the overall reaction that takes place in a hydrogen fuel cell.
Answer/Explanation
Answer:
(a) distillation (1)
fractional (1)
(b) naphtha (1)
bitumen (1)
(c) (i) any two from:
methane ethane propane
(ii) \(2C_4H_{10} + 13O_2 \rightarrow 8CO_2 + 10H_2O\)
\(CO_2\) and \(H_2O\) as products (1) correct equation (1)
(iii) carbon monoxide
(d) (i) kerosene is more viscous
gasoline is more flammable
(ii) kerosene has molecules with a longer carbon chain
(e) hydrogen + oxygen \(\rightarrow \) water
Question
Biogas is made by fermenting animal and vegetable waste.
(a) The table shows the percentage composition of the gases present in a sample of biogas.
Deduce the percentage of nitrogen present in this sample of biogas.[1]
(b) (i) Balance the chemical equation for the complete combustion of methane.
CH4 + __ O2 → CO2 + __ H2O [2]
(ii) Which one of these compounds belongs to the same homologous series as methane?
Draw a circle around the correct answer.
methanolic acid methanol propane propanol propene [1]
(iii) Methane is present in the refinery gas fraction produced by the fractional distillation of petroleum.
Match the fractions on the left with their uses on the right.
The first one has been done for you.
(c) (i) Draw a dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen. [1]
(ii) State one use of hydrogen.[1]
(d) The biogas contains a small amount of compound C.
The structure of compound C is shown.
(i) On the structure shown, draw a circle around the carboxylic acid functional group. [1]
(ii) How many different types of atoms are present in compound C?[1]
(e) Describe the manufacture of ethanol by fermentation.
In your answer include:
- the names of the substances needed for fermentation
- the conditions needed for fermentation. [4] [Total: 14]
Answer/Explanation
Ans:
(a) 6.0 / 6 (%)
(b)(i) 2 (O2) (1)
2 (H2O) (1)
(b)(ii) propane
(b)(iii) 3 correct (2)
1 or 2 correct (1)
fuel oil → fuel for ships
bitumen → making roads
naphtha → making chemicals
(c)(i) two (hydrogen) atoms with pair of electrons between and no other electrons
(c)(ii) fuel
(d)(i) circle around the COOH group only
(d)(ii) 5
(e) glucose / sugar (1)
yeast (1)
AND
1 mark each for any two of:
-
- oxygen absent / anaerobic
- room temperature / stated temperature between 5 °C and 40 °C (inclusive)
- pH near neutral
- presence of water / aqueous solution
- purify by distillation
Question
Petroleum is a source of many important chemicals.
(a) Name two industrial processes which must take place to produce alkenes from petroleum.
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….. [2]
(b) Ethene, CH2=CH2, and propene, \(CH_2=CHCH_3\), can both be converted into polymers.
(i) What type of polymerisation takes place when ethene forms a polymer?
……………………………………………………………………………………………………………………… [1]
(ii) What is the empirical formula of the polymer formed from ethene?
……………………………………………………………………………………………………………………… [1]
(iii) Propene has the structural formula \(CH_2=CHCH_3\).
Draw two repeat units of the polymer made from propene.
[2]
(c) Ethene will react with steam to form ethanol. Propene will react with steam to form two isomers, both of which are alcohols. Suggest the structures of these alcohols.
(d) Esters are organic chemicals noted for their characteristic smells. Ethanoic acid and methanol will react to form an ester.
(i) Name the catalyst needed to form an ester from ethanoic acid and methanol.
……………………………………………………………………………………………………………………… [1]
(ii) Name the ester formed when ethanoic acid reacts with methanol.
……………………………………………………………………………………………………………………… [1]
(iii) Draw the structure of the ester formed when ethanoic acid reacts with methanol. Show all bonds.
Answer/Explanation
6(a)
fractional distillation;
cracking;
6(b)(i) addition;
6(b)(ii) \(CH_2\);
6(b)(iii)
M1 chain of 4 carbon atoms with single bonds and continuation bonds;
M2 correctly positioned \(CH_3\) side chains;
6(d)(iii)
6(d)(i) (concentrated) sulfuric acid;
6(d)(ii) methyl ethanoate;
6(d)(iii)
M1 ester link;
M2 rest of molecule;
6(d)(iv) terylene;