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7.1 Organic Chemistry – Low Demand 2 – Qs
Q1.A teacher carried out an experiment to study car engine oil. The experiment was carried out in a fume cupboard and the teacher wore plastic gloves. The oil was poured through a funnel. The time taken for all the oil to go through the funnel was measured. The experiment was repeated with the oil at different temperatures.
(a) What two safety precautions were taken in the experiment?
1. _________________________________________________________________
2. _________________________________________________________________(1)
(b) The results of the experiment are shown in the table below.
(i) Plot the results on the graph paper. One of the results has been plotted for you. Join the points in a smooth curve.
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(3)
(ii) Use your graph to find the time it would take the oil to travel through the funnel at 37 °C.
Time = ____________________ seconds(1)
(iii) How does the time taken for the oil to go through the funnel change when the temperature is increased?
______________________________________________________________
______________________________________________________________(1)
(c) An engine oil must be viscous enough to stop the metal parts of the engine from rubbing against each other. It must not be too viscous or the parts cannot move freely.
(i) Complete the sentences below.
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The more viscous a liquid is, the less easily it _____________________ .
As the liquid gets hotter it gets ___________________________ viscous.(2)
(ii) Why should the oil in a car engine not be allowed to get too hot?
______________________________________________________________
______________________________________________________________
______________________________________________________________(1)
(Total 9 marks)
Q2.Crude oil contains many different hydrocarbons.
(i) Which formula in the list represents a hydrocarbon?Draw a ring around the correct formula.
CO2 C6H12O6 C8H18 H2O(1)
(ii) Which word from the list below best describes crude oil?Draw a ring around the correct word.
alloy compound element mixture(1)
(iii) Choose, from the list below, words to complete the passage about the separation of the hydrocarbons in crude oil by fractional distillation.
atoms burned condensed evaporated filtered
fractions ions molecules neutralised
During fractional distillation the many hydrocarbons in crude oil are separated
into _________________ each of which contains ________________ with a
similar number of carbon __________________ .
To do this the oil is first __________________ and then __________________
at a number of different temperatures.(5)
(Total 7 marks)
Q3.Crude oil is a mixture of hydrocarbons. These hydrocarbons can be separated and some of them can be used to make other useful products.
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(a) Complete the sentence.
Hydrocarbons are made up of ________________ atoms and ________________ atoms.
(2)
(b) How are the small and large hydrocarbon molecules in crude oil separated?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________(2)
(c) The diagram shows that one useful product of cracking is fuels.Name one of the other useful products.
___________________________________________________________________(1)
(Total 5 marks)
Q4.The table shows the composition of some crude oil.
Fraction Percentage in crude oil
Gases 3
Petrol 7
Naphtha 10
Kerosine 15
Gas oil 20
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Fuel oil 45
(a) Complete the pie chart for the composition of this crude oil. Remember to label the chart.
(3)
(b) The diagram shows the process of separating a different sample of crude oil into fractions.
(i) What is the name given to this process?
______________________________________________________________(1)
(ii) Which fraction has the lowest boiling point?
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______________________________________________________________(1)
(iii) Which fraction is the least volatile?
______________________________________________________________(1)
(Total 6 marks)
Q5.Crude oil and natural gas are mixtures of hydrocarbons. They are obtained from wells drilled into rocks where they are trapped.
(a) (i) What is the name of the process used to separate the different hydrocarbons in crude oil?
______________________________________________________________(1)
(ii) Methane is one of the gases obtained when crude oil is separated.
Give the name of another hydrocarbon gas obtained from this process.
______________________________________________________________(1)
(b) A fuel used in gas cookers is natural gas. It is mainly methane, CH4.
(i) Complete the word equation for the complete combustion of methane.
methane + oxygen → __________________ + _______________________(2)
(ii) What different gas is produced by the incomplete combustion of methane?
______________________________________________________________(1)
(Total 5 marks)
Q6.Wax is a fuel.
A young child watched a candle burning and wondered where the wax had gone.
(a) Complete the sentence below.
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When wax burns, energy is released as ___________________________________(1)
(b) Why does the wax disappear as it burns?
___________________________________________________________________
___________________________________________________________________(1)
(Total 2 marks)
Q7.This experiment shows a candle burning then going out.
(a) Choose words from this list to complete the sentences in parts (i) and (ii) below.
air carbon dioxide hydrogen nitrogen oxygen
(i) When the candle wax is burning it is reacting with ___________________
from the __________________________ .(2)
(ii) One product of the reaction is _____________________________________(1)
(b) Complete the following sentence.
In another experiment a 200 cm3 beaker is used. The candle will then burn
for about ______________________ seconds.(1)
(Total 4 marks)
Q8.Natural gas is a fuel.
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(a) Complete these sentences.
When the fuel burns completely, we cannot see the new substances produced because
they are mainly colourless ____________________________ .
The energy of the fuel is released as ____________________ .(3)
(b) Choose words from this list to complete the sentence below.
carbon carbon dioxide hydrogen nitrogen
oxygen sulphur dioxide water vapour
Three gases which can be produced when fuels burn are:
1. _________________________________________________________________
2. _________________________________________________________________
3. _________________________________________________________________(3)
(Total 6 marks)
Q9.The gases produced when coal burns are cooled by ice and then bubbled through limewater.
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(a) Complete these sentences.
(i) The coal is reacting with ________________________ when it burns.
(ii) During burning, elements in the coal are converted to compounds
called ______________________________.(2)
(b) Choose words from this list to complete the sentences.
carbon carbon dioxide sulphur sulphur dioxide
sodium water
(i) Liquid X is a compound made from hydrogen and oxygen.
It is called _____________________________________________________
(ii) Sulphur dioxide is an acidic gas. It is given off when coal burns, because coal
contains the element _____________________________________________
(iii) Most fuels are compounds of hydrogen and __________________________(3)
(c) Burning coal is an exothermic reaction.
Explain what “exothermic” means.
___________________________________________________________________
___________________________________________________________________(1)
(d) (i) Which gas turns limewater cloudy?
______________________________________________________________
(ii) Which element in the coal is oxidised to form this gas?
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______________________________________________________________(2)
(Total 8 marks)
Q10.Crude oil is separated into fractions by distillation.
Each fraction contains hydrocarbon molecules of a similar size.
The table shows information about two fractions obtained when crude oil is distilled.
Fraction Supplyfrom distillation aspercentage (%) of
crude oil input
Demandby consumers aspercentage (%) of
crude oil input
Number ofcarbon atoms in
hydrocarbon chain
Petrol 14 27 C5 – C10
Kerosene 13 8 C11 – C15
(a) Some of the kerosene fraction is made into petrol.
Use the table to suggest two reasons why kerosene is used to make petrol.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________(2)
(b) Use the correct word from the box to complete each sentence.
boiling catalyst cracking filtration polymer
Kerosene is made into petrol by a process called ______________________ .
Kerosene is heated.
The hydrocarbons vaporise.
The gases are passed over a hot ______________________ .(2)
(Total 4 marks)
Q11.The figure below shows a power station.
Fossil fuels are burnt at some power stations.
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© Uli Hamacher/iStock
(a) Draw a ring around the correct answer to complete the sentence.
Fossil fuels release energy by
combustion. decomposition. distillation.
(1)
(b) Burning fuels can also release substances which cause an environmental effect.
Draw one line from each substance to an environmental effect caused by the substance.
Substance Environmental effect
Acid rain
Carbon dioxide
Bioleaching
Oxides of nitrogen
Global dimming
Solid particles
Global warming
(3)(Total 4 marks)
Q12.Fire dancers use firesticks to make flame patterns.
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One end of the firestick is soaked in kerosene.The kerosene is lit and burns with a yellow flame.
Kerosene is a mixture of hydrocarbons.
(a) Complete the following sentence.
A hydrocarbon is made up of only two elements, _____________________ and carbon.
(1)
(b) A student investigated the products formed when kerosene burned.
Diagram 1 shows the apparatus the student used.
Diagram 1
(i) The limewater turns cloudy.
Name the gas that turns limewater cloudy.
______________________________________________________________(1)
(ii) Name the colourless liquid collected in the U–tube.
______________________________________________________________(1)
(c) Kerosene is obtained from crude oil.
Crude oil is separated into fractions.
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The process is called fractional distillation.
Diagram 2
Use only information from Diagram 2 to help you to answer these questions.
(i) Which of the named fractions has the lowest boiling point?
______________________________________________________________(1)
(ii) Which of the named fractions is the most viscous (thickest)?
______________________________________________________________(1)
(iii) Use the correct word from the box to complete the sentence.
fuels metals plastics
All the fractions listed in Diagram 2 can be used as ___________________ .(1)
(d) Crude oil is separated by fractional distillation.
The statements, A, B, C, D and E, describe how different fractions are obtained from crude oil.
A crude oil is heatedB hydrocarbons condenseC hydrocarbon vapours enter the fractionating columnD hydrocarbons with higher boiling points condense near the bottom of the column
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E crude oil vaporises
Complete the sequence below. Put the statements, A, B, C, D and E, in the correct order to show how crude oil is separated into fractions.
The first and last boxes have been completed for you.
(2)
(Total 8 marks)
Q13.Vehicles need fuel to power them.
Some of these fuels are obtained from crude oil.
Jet © Dimitar Marinov/iStock Truck © James McQuillan/iStock Car © tridland/iStock
(a) (i) Draw a ring around the correct answer to complete the sentence.
Crude oil contains many compounds.
an alloy.
Crude oil is an element.
a mixture.
(1)
(ii) Draw a ring around the correct answer to complete the sentence.
Crude oil can be separated into fractions by evaporating the crude oil. The fractions then condense separately.
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combustion.
This process is called fractional decomposition.
distillation.
(1)
(b) The different fractions have different properties.
Fraction Number of carbon atoms
Boiling point range in°C
Flash point in°C
Petrol 5–10 40–180 -43
Kerosene 10–15 180–250 38
Diesel 15–20 250–300 63
Flash point is the lowest temperature at which the fuel will catch fire.
How does increasing the number of carbon atoms affect the boiling point and flash point of the fractions in crude oil?
Complete the sentences.
As the number of carbon atoms increases, the boiling point ___________________
___________________________________________________________________
As the number of carbon atoms increases, the flash point ____________________
___________________________________________________________________(2)
(c) Octane is one of the compounds in petrol.
An octane molecule has 8 carbon atoms.
(i) Predict the boiling point of octane.
____________________°C(1)
(ii) Octane is an alkane. The general formula for alkanes is CnH2n+2
What is the formula of octane?
______________________________________________________________(1)
(Total 6 marks)
Q14.In the laboratory, ethene can be made when heptane vapour is passed over a hot catalyst.
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Heptane is an alkane.
(a) (i) Draw a ring around the correct answer to complete the sentence.
combustion.
The process used to make ethene is called cracking.
fermentation.
(1)
(ii) Why does pentane collect in the test tube surrounded by cold water?
______________________________________________________________
______________________________________________________________(1)
(iii) Complete the sentences using words from the labels on the diagram.
The name of the alkane that decomposes is ___________________ .
The name of the catalyst is _________________________________(2)
(b) The displayed (structural) formula of ethene is:
Ethene is added to bromine water.
What colour change will be seen when ethene is added to bromine water?
___________________________________________________________________
___________________________________________________________________
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___________________________________________________________________
___________________________________________________________________(2)
(c) Name the polymer made from ethene.
___________________________________________________________________(1)
(Total 7 marks)
Q15.Hydrocarbons are cracked to produce smaller molecules.
(a) Use words from the box to complete each sentence.
alkanes emulsions fuels monomers polymers
Some of the products of cracking can be used in cars as ____________________ .
The products of cracking include alkenes and saturated hydrocarbons
called ________________________ .
Alkenes can be used in reactions to make large molecules
called ________________________ .
The many small molecules that join up to form a large molecule are known
as ________________________ .(4)
(b) The diagram shows an experiment to demonstrate cracking.
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Complete each sentence below.
The broken pottery acts as a ________________________ .
The name of the liquid hydrocarbon produced by the cracking
is ________________________ .
The name of the alkene produced by the cracking is ________________________ .(3)
(Total 7 marks)
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