Crude oil, hydrocarbons & alkanes

Crude oil is a mixture of compounds.

Most of the compounds are hydrocarbons called alkanes.

Propane is an alkane.

The formula of propane is C₃H₈

Complete the general formula for alkanes.

C_nH _________

Table 4 shows information about some alkanes.

Predict the value of X in Table 4.

Explain the trend in boiling points shown in Table 4.

Propane is used as a fuel.

Write a balanced equation for the complete combustion of propane (C₃H₈).

Hydrocarbons in crude oil are separated into fractions using fractional distillation.

Figure 16 shows a fractional distillation column.

Explain how crude oil is separated into fractions by fractional distillation.

How do the viscosity and boiling point of heavy fuel oil compare with the other fractions in Figure 16 ?

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Heavy fuel oil is the least viscous and has the highest boiling point.

Heavy fuel oil is the least viscous and has the lowest boiling point.

Heavy fuel oil is the most viscous and has the highest boiling point.

Heavy fuel oil is the most viscous and has the lowest boiling point.

This question is about hydrocarbons.

Name the two elements in a hydrocarbon.

Which two of the following substances are hydrocarbons?

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Ammonia

Ethene

Graphite

Methane

Steam

C₆H₁₄ is a hydrocarbon.

C₆H₁₄ can be broken down into smaller molecules.

Complete the equation for the breakdown of C₆H₁₄ into smaller molecules.

What is the name of the process t hat breaks d own C₆H₁₄ into smaller molecules?

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Cracking

Distillation

Neutralisation

How does the boiling point of C₆H₁₄ compare with the boiling point of C₄H₁₀?

Give one reason for your answer.

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C₆H₁₄ has a lower boiling point.

C₆H₁₄ and C₄H₁₀ have the same boiling point.

C₆H₁₄ has a higher boiling point.

The complete combustion of C₆H₁₄ produces water and one other product.

Name the other product of the complete combustion of C₆H₁₄

Do not refer to water in your answer.

The formula of water is H₂O

Calculate the relative formula mass (M_r) of water.

Relative atomic masses (A_r): H = 1 O = 16

This question is about hydrocarbons.

Hexane (C₆H₁₄) and pentane (C₅H₁₂) are hydrocarbons in the same homologous series.

Give the name of the homologous series that includes hexane and pentane.

Give the general formula of the homologous series that includes hexane and pentane.

Explain why the boiling point of hexane is higher than the boiling point of pentane.

Complete the equation for the cracking of hexane (C₆H₁₄) into ethene and one other molecule.

Methane undergoes complete combustion with oxygen.

Figure 10 represents the equation for the reaction.

Figure 10

The energy released forming the new bonds is 814 kJ/mol greater than the energy needed to break the existing bonds.

Table 4 shows some bond energy values.

Calculate value Y in Table 4.

_ Y = ____________________ kJ/mol

This question is about hydrocarbons.

What is the maximum number of bonds that one carbon atom can form?

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2 3 4 6

Most of the compounds in crude oil are hydrocarbons.

Crude oil is the remains of an ancient biomass.

What did the ancient biomass mainly consist of?

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Methane

Plankton

Rocks

Fractional distillation is used to separate the hydrocarbons in crude oil into fractions.

Which property of hydrocarbons is used to separate them?

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Boiling point

Flammability

Viscosity

Name one fuel produced from the fractional distillation of crude oil.

What are the two products of the complete combustion of a hydrocarbon?

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Ammonia

Carbon dioxide

Nitrogen

Oxygen

Water

How does the size of the molecules affect the viscosity of hydrocarbons?

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Smaller hydrocarbon molecules have greater viscosity.

The size of the hydrocarbon molecules does not affect the viscosity.

Larger hydrocarbon molecules have greater viscosity.

This question is about carbon and carbon compounds.

Carbon forms compounds called alkanes.

Which formula represents an alkane molecule with 8 carbon atoms?

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C₈H₁₀

C₈H₁₄

C₈H₁₆

C₈H₁₈

Alkanes can be cracked.

Name one method of cracking alkanes.

Explain how cracking alkanes helps to meet the demand for fuels.

Ethene can be produced when alkanes are cracked.

The formula of ethene is C₂H₄

Calculate the simplest whole number ratio by mass of carbon to hydrogen in ethene.

Relative atomic masses (A_r): C = 12 H = 1

Ratio by mass of carbon: hydrogen = ______________: ______________

Carbon exists in different forms.

Which form has each carbon atom bonding with four other carbon atoms?

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Diamond

Graphene

Graphite

Fullerene molecules are made of carbon atoms.

Give two other features of the structure of fullerene molecules.

A carbon nanotube has:

a length to diameter ratio of 6 900 000: 1

Calculate the length of the carbon nanotube in nm.

Explain why carbon nanotubes are good conductors of electricity.

Crude oil is a mixture containing hydrocarbons.

Alkanes are hydrocarbons.

Figure 10 represents an alkane.

X and Y represent atoms of different elements in an alkane.

Label element X and element Y on Figure 10.

What is represented by Z on Figure 10 ?

Crude oil is separated into fractions in a fractionating column.

Figure 11 shows a fractionating column.

Table 2 gives some properties of different fractions separated from crude oil.

Label Figure 11 to show where diesel, heavy fuel oil and kerosene fractions are collected.

Use Table 2.

Complete the sentences.

Choose answers from the box.

Which statement about the flammability of petrol and diesel is correct?

Use Table 2.

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Table 2 is repeated here.

Octane is a hydrocarbon obtained from crude oil.

Octane has 8 carbon atoms.

Which fraction in Table 2 contains octane?

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Name the two substances produced from the complete combustion of octane.

This question is about the hydrocarbons obtained from crude oil.

Octane is a hydrocarbon.

How does the formula of octane show that octane is an alkane?

The fractions in crude oil are separated by fractional distillation.

Figure 6 shows a fractionating column.

Table 3 gives some properties of different fractions separated from crude oil.

Which fraction in Table 3 is the most viscous?

Give one reason for your answer.

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Describe how the fraction containing octane is separated from crude oil.

Use data from Table 3 in your answer.

This question is about hydrocarbons.

Figure 6 represents hydrocarbon A.

Complete the chemical formula of hydrocarbon A.

C₅

What do the links between the atoms in Figure 6 represent?

Hydrocarbon A is a fuel. Hydrocarbon A is completely combusted in air.

Which two substances are produced?

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Some students investigated how changing the temperature of a hydrocarbon affects the viscosity of the hydrocarbon.

Figure 7 shows the apparatus used.

The students recorded the time it took for 25 cm³ of the hydrocarbon to flow through the hole in the viscometer.

Table 3 shows a student’s results at 60 °C

Calculate the mean value X.

Another student investigated a different hydrocarbon.

Table 4 shows the results.

Complete Figure 8.

You should:

• plot the data from Table 4

• draw a line of best fit.

Describe the pattern shown on Figure 8.

The viscosity of a substance is linked to how fast the substance flows.

The lower the viscosity, the faster the substance flows.

Complete the sentence.

Choose the answer from the box.

As the temperature increases, the viscosity of

the hydrocarbon.