Cracking and alkenes

Crude oil is a source of hydrocarbons.

Which chemical is a hydrocarbon?

Tick (✓) one box.

Complete the sentences about crude oil.

Use words from the list.

cracking filtration fractional distillation neutralisation reduction

The hydrocarbons in crude oil are separated by........

Some of these hydrocarbons are made more useful by........

The table shows the description of three resources A, B and C.

Which resource is crude oil?

Explain your choice using information from the table.

Crude oil is resource........

Reason........

Scientists think that increased levels of carbon dioxide are causing global warming.

Which statements about the potential effects of global warming are true and which are false ?

Tick (✓) one box in each row.

What are the optimum reaction conditions for the cracking of hydrocarbons?

Crude oil is a source of useful chemicals called hydrocarbons.

Complete the sentence about crude oil.

Crude oil is a compound / feedstock / renewable resource used by the petrochemical industry.

The diagram shows the fractionating column used in the fractional distillation of crude oil.

Which state symbol describes the crude oil as it enters the fractionating column?

Tick (✓) one box.

Write an X on the fractionating column where it is coolest.

The table shows the boiling point of four hydrocarbons.

Which of the hydrocarbons P, Q, R or S is produced nearest to the top of the fractionating column?

Which of the hydrocarbons P, Q, R or S has the largest molecules?

Large hydrocarbons can be made more useful by cracking.

The equation shows the cracking of hydrocarbon X.

What is the formula of hydrocarbon X ?

Which homologous series of hydrocarbons does C₆H₁₄ belong to?

The hydrocarbon C₂H₄ belongs to a different homologous series.

Suggest the general formula of the homologous series that contains C₂H₄.

Tick one (✓) box.

The graph shows the supply and demand of different fractions of crude oil.

Which fractions are most likely to be cracked to make the supply match the demand?

A Diesel and fuel oil

B Gases and petrol

C Paraffin and fuel oil

D Petrol and diesel

The equation shows a reaction of decane, C₁₀H₂₂, when it is heated with a catalyst.

C₁₀H₂₂ → C₅H₁₂ + C₃H₆ + C₂H₄

What is the name of this process?

A Cracking

B Displacement

C Electrolysis

D Reduction

The processing of crude oil by the petrochemical industry can be shown by different experiments.

Fig. 14.1 shows an experiment where paraffin is turned into decane and gas X.

Fig. 14.1

Fig. 14.2 shows the reaction of paraffin, C₁₄H₃₀, to make decane, C₁₀H₂₂, and gas X.

Fig. 14.2

Complete the sentences below to describe the experiment.

The experiment is called cracking / displacement / distillation.

It is an example of combustion / reduction / thermal decomposition.

The porous pot in Fig. 14.1 acts as a catalyst in the reaction.

What effect does the porous pot have on the rate of the reaction ?

decreases it
increases it
no effect

What effect does the porous pot have on the activation energy of the reaction?

decreases it
increases it
no effect

Use Fig. 14.2 to answer these questions.

Write the formula of gas X.

Describe what happens to a molecule of paraffin as it turns into a molecule of decane.

The equation shows the reaction for the cracking of the alkane C₁₅H₃₂.

What is the formula of X ?

A C₃H₆

B C₃H₈

C C₅H₁₀

D C₅H₁₂

Crude oil is a mixture of alkanes which can be separated into different fractions.

The different fractions have a range of different boiling points.

The diagram shows the process of fractional distillation.

Explain how fractional distillation separates the crude oil into fractions.

Icosane, C₂₀H₄₂, is an alkane found in one of the fractions.

It has a boiling point of 343 °C.

Which fraction, A, B, C, D, E or F, contains icosane?

Icosane is converted into more useful products by cracking.

State the two conditions used for cracking.

Many different products can form when cracking icosane.

In one reaction, a molecule of icosane (C₂₀H₄₂) forms a molecule of hydrogen, H₂, and one other product.

Write the balanced symbol equation for this reaction.

* Fraction A contains the alkanes methane, ethane, propane and butane.

Table 14.1 shows some information about these four alkanes.

Describe and explain the similarities and differences in the boiling point of these four alkanes.

Use information in Table 14.1 and your knowledge of structure and bonding in your answer.

Look at the flowchart. It shows how crude oil is changed into useful substances.

Complete the flowchart with the name of Process 2.

Table 11.1 shows the supply and demand of two fractions of crude oil.

Explain the importance of Process 2.

Use information from Table 11.1 in your answer.

The hydrocarbon fractions from Process 1 contain different alkanes.

Table 11.2 shows the boiling point of different alkanes produced in Process 1.

Complete Table 11.2 with an estimate of the missing boiling point for an alkane molecule

with 3 carbon atoms.

Write the formula for an alkane with 7 carbon atoms.

Crude oil can be separated into useful substances called fractions.

Write down the name of the process that separates crude oil into fractions.

Name the fractions A and B.

A........

B........

Here are the boiling ranges for petrol and diesel.

How do the sizes of molecules in petrol and diesel differ?

Explain why the boiling range for petrol is different from the boiling range for diesel.

Not enough petrol is made from crude oil to meet world demand.

Oil refineries make more petrol using a process called cracking.

Describe how cracking makes more petrol from other hydrocarbons.

Include the conditions needed.