Worksheet: Cracking of Hydrocarbons

In this worksheet, we will practice explaining the catalytic cracking of alkanes and its importance and describing the process on an industrial scale.

Q1:

Which type of chemical reaction is cracking an example of?

  • ACondensation
  • BAddition
  • CDisplacement
  • DHydrolysis
  • EDecomposition

Q2:

The cracking of a nonane molecule can produce a range of products.

If the cracking of a nonane molecule produces two molecules including propene, what is the name of the second product?

  • AHexane
  • BPentane
  • CPentene
  • DHeptene
  • EHexene

Which of the following pairs of molecules can be produced by the cracking of a nonane molecule, assuming there are no other products?

  • AEthene + hexene
  • BHexene + propene
  • CPropane + heptene
  • DButane + pentene
  • EOctane + methane

Which of the following groups of molecules can be produced by the cracking of a nonane molecule, assuming there are no other products?

  • APropene + propene + propene
  • BEthene + ethane + pentane
  • CHexene + propane + ethene
  • DPropane + ethene + butene
  • EButene + propane + methane

Q3:

Which of the following statements is true?

  • ACracking increases the chain length of the hydrocarbon.
  • BCracking always generates gaseous products.
  • CCracking is a method of polymerization.
  • DCracking is possible without a catalyst.
  • ECracking is exothermic.

Q4:

In which of the following properties is an increase observed when hydrocarbon fuels undergo cracking?

  • AMelting point
  • BVolatility
  • CViscosity
  • DMolecular size
  • EIgnition temperature

Q5:

In catalytic cracking, a gaseous hydrocarbon flows over a heated catalyst and is converted to more valuable products. Which of the following catalyst properties cannot be increased to produce a higher reaction rate?

  • ATemperature
  • BParticle size
  • CSurface area
  • DMass
  • EPorosity

Q6:

Cracking may be used to convert one fraction of crude oil to a mixture of hydrocarbons with the properties of a different fraction. Which of the following fuels can be replicated via the cracking of kerosene?

  • AGasoline and LPG
  • BLPG only
  • CDiesel oil and gasoline
  • DDiesel oil, gasoline, and LPG
  • EGasoline only

Q7:

In which range of temperatures is catalytic cracking usually performed?

  • A 3 0 0 5 0 0 C
  • B 0 1 0 0 C
  • C 1 0 0 3 0 0 C
  • D 7 0 0 9 0 0 C
  • E 5 0 0 7 0 0 C

Q8:

A hydrocarbon has the structural formula shown:

The cracking of this hydrocarbon can produce a range of products.

What is the molecular formula of this hydrocarbon?

  • A C H 1 0 2 2
  • B C H 1 0 2 0
  • C C H 8 1 6
  • D C H 9 1 8
  • E C H 8 1 8

What are the structural formulas of the products when one molecule of this hydrocarbon undergoes a single cracking reaction?

  • A
  • B
  • C
  • D
  • E

Q9:

Hydrocarbons X and Y are produced by cracking decane (CH)1022. The molecular formula of X is CH612.

What is the molecular formula of Y?

  • A C H 4 8
  • B C H 6 1 4
  • C C H 6 1 0
  • D C H 4 1 0
  • E C H 5 1 0

Which diagram illustrates the appearance of a glowing splint after exposure to the vapor of compound X in air?

  • A
  • B
  • C
  • D
  • E

Which diagram illustrates a test tube of bromine water after the addition of a large quantity of compound X?

  • A
  • B
  • C
  • D
  • E

Which diagram illustrates a test tube of potassium permanganate solution after the addition of a large quantity of compound Y?

  • A
  • B
  • C
  • D
  • E

Q10:

Under which of the following conditions is thermal cracking usually performed?

  • ALow temperature and high pressure
  • BHigh temperature and low pressure
  • CHigh temperature and high pressure
  • DLow temperature and low pressure

Q11:

An alkane undergoes three different cracking reactions to produce a range of compounds, as shown by the equations.

At room temperature and pressure, compounds W, Y, and Z are gases and compound X is a liquid. The results of testing the compounds with bromine water are shown in the diagram.

B r 2 ( aq ) X Z W Y X Z W Y

What is the displayed formula of compound W?

  • A
  • B
  • C
  • D
    C H C H C H H H C H H H
  • E

What is the displayed formula of compound X?

  • A
  • B
  • C
  • D
  • E

What is the displayed formula of compound Y?

  • A
  • B
  • C
  • D
  • E

What is the displayed formula of compound Z?

  • A
  • B
  • C
  • D
  • E

Q12:

Shown in the equation is one possible reaction in the cracking of heptane:

+ X C H H H C H C H C H H H H C C H H C H H H H H C H C H H H C H H

Compound X is an unbranched hydrocarbon. What is the displayed formula of compound X?

  • A
    C H C H C H H C H H H H
  • B
    C H C H H H H C C H H H H H
  • C
    C H H H C C H H H H H
  • D
    C C H C H H C H H H H H C H H
  • E
    C H C H H H C H H C H H H C H H H

Q13:

Cracking of compound X produces smaller molecules according to the equation shown:

Compound X is an unbranched hydrocarbon. What is the displayed formula of compound X?

  • A
  • B
  • C
  • D
  • E

Q14:

During catalytic cracking of a hydrocarbon mixture, a molecule X reacts according to the equation shown:

Which of the following is a possible structural formula for the reacting molecule?

  • A
  • B
  • C
  • D
  • E