A mixture of many different hydrocarbons.

What is a hydrocarbon?

A compound containing only hydrogen and carbon atoms.

Describe how fractional distillation works.

Crude oil is vaporised and enters a column that is hot at the bottom and cooler at the top. Each hydrocarbon condenses at the height where the temperature is below its boiling point.

A group of hydrocarbons with similar boiling points, collected together.

How do chain length and boiling point change from the top to the bottom of the column?

Chains get longer and boiling points get higher towards the bottom.

Why are alkanes called saturated?

They contain only single carbon–carbon bonds, so they hold the maximum number of hydrogen atoms.

Name the first four alkanes with their formulae.

Methane CH₄, ethane C₂H₆, propane C₃H₈, butane C₄H₁₀.

Name alkanes with 5 to 10 carbon atoms.

Pentane, hexane, heptane, octane, nonane, decane.

What is the difference between a structural and a displayed formula?

A structural formula groups the atoms (CH₃CH₂CH₃); a displayed formula shows every atom and every bond.

Write the word equation for complete combustion of an alkane.

Alkane + oxygen → carbon dioxide + water.

Write the balanced equation for the complete combustion of methane.

CH₄ + 2O₂ → CO₂ + 2H₂O

What are the products of incomplete combustion?

Carbon monoxide and/or carbon (soot), plus water.

Why is carbon monoxide dangerous?

It is a toxic gas that stops blood carrying oxygen, and it is colourless and odourless.

Hydrocarbons and alkanesIB MYP Chemistry: Flashcards

Card 1 of 150 of 15 known

Question

What is crude oil?

Tap or press Space to reveal

Tap card or press Space to flip

See all 15 cards

What is crude oil?: A mixture of many different hydrocarbons.
What is a hydrocarbon?: A compound containing only hydrogen and carbon atoms.
Describe how fractional distillation works.: Crude oil is vaporised and enters a column that is hot at the bottom and cooler at the top. Each hydrocarbon condenses at the height where the temperature is below its boiling point.
What is a fraction?: A group of hydrocarbons with similar boiling points, collected together.
How do chain length and boiling point change from the top to the bottom of the column?: Chains get longer and boiling points get higher towards the bottom.
What is the general formula of the alkanes?: CₙH₂ₙ₊₂
Why are alkanes called saturated?: They contain only single carbon–carbon bonds, so they hold the maximum number of hydrogen atoms.
Name the first four alkanes with their formulae.: Methane CH₄, ethane C₂H₆, propane C₃H₈, butane C₄H₁₀.
Name alkanes with 5 to 10 carbon atoms.: Pentane, hexane, heptane, octane, nonane, decane.
What is the formula of octane?: C₈H₁₈
What is the difference between a structural and a displayed formula?: A structural formula groups the atoms (CH₃CH₂CH₃); a displayed formula shows every atom and every bond.
Write the word equation for complete combustion of an alkane.: Alkane + oxygen → carbon dioxide + water.
Write the balanced equation for the complete combustion of methane.: CH₄ + 2O₂ → CO₂ + 2H₂O
What are the products of incomplete combustion?: Carbon monoxide and/or carbon (soot), plus water.
Why is carbon monoxide dangerous?: It is a toxic gas that stops blood carrying oxygen, and it is colourless and odourless.

Exam questions on Hydrocarbons and alkanes

A refinery in Rotterdam heats crude oil until most of it has vaporised and then feeds it into a tall fractionating column. The column is hot at the bottom and much cooler at the top. Different products are drawn off at different heights.
Explain how fractional distillation separates the hydrocarbons in crude oil into fractions.2 marks
A student is given the molecular formulae of a series of hydrocarbons: CH₄, C₂H₆, C₃H₈, C₄H₁₀ and C₅H₁₂.
Explain why propane, C₃H₈, is described as a saturated hydrocarbon.2 marks
A student in Mexico City investigates what is produced when methane, the main gas in natural gas, burns in a Bunsen burner with the air hole open. She holds a cold, dry glass funnel above the flame and connects it by a tube to a boiling tube containing limewater.
Describe how the student could use the apparatus to show that burning methane produces both water and carbon dioxide.3 marks

See the full worksheet

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).