Sciences - Co-ordinated (Double) - 0654 CIE

Alkanes

Overview

The alkanes are the simplest and most familiar organic family: the methane in natural gas, the propane in camping stoves, the petrol in cars. They are the workhorse fuels of the modern world, prized for the energy they release when they burn.

In this lesson you will learn that alkanes are saturated hydrocarbons with the general formula CnH2n+2, why they are generally unreactive, and the two reactions you must know: combustion in air and substitution with halogens in ultraviolet light.

Objectives

State that the bonding in alkanes is single covalent and that alkanes are saturated hydrocarbons.
Describe the properties of alkanes as being generally unreactive, except in terms of combustion and substitution by chlorine.
[Supplement] State that in a substitution reaction one atom or group of atoms is replaced by another atom or group of atoms.
[Supplement] Describe the substitution reaction of alkanes with chlorine as a photochemical reaction, with ultraviolet light providing the activation energy, E , and draw the structural or a displayed formulae of the products, limited to monosubstitution.

Lesson Note

Alkanes provide most of the fuels we depend on, so understanding how they burn matters for energy, transport and the environment. Their general lack of reactivity also makes them a useful baseline, the calm starting point against which the more reactive families are compared.

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Lesson Evaluation

Congratulations on completing the lesson on Alkanes. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

Alkanes are described as saturated because they contain only: A. Double bonds B. Single carbon-carbon bonds C. Triple bonds D. Functional groups Answer: B
The general formula of the alkanes is: A. CnH2n B. CnH2n+2 C. CnH2n-2 D. CnH2n+1OH Answer: B
Complete combustion of an alkane produces: A. Carbon monoxide and water B. Carbon dioxide and water C. Hydrogen and carbon D. Carbon dioxide only Answer: B
The reaction of methane with chlorine in UV light is a: A. Addition reaction B. Neutralisation C. Substitution reaction D. Combustion reaction Answer: C
Which condition is needed for an alkane to react with chlorine? A. A catalyst B. Ultraviolet light C. High pressure D. An acid Answer: B