Alkanes

Question 1

What does it mean when alkanes are described as ‘saturated hydrocarbons’?

Answer 1

Saturated- contains only single covalent bonds
Hydrocarbons- contains only carbon and hydrogen atoms

Saturated hydrocarbons have the maximum number of hydrogen atoms per carbon atom.

Question 2

Describe the bonding in alkanes

Answer 2

Saturated (only contain single covalent bonds). Each carbon atom forms four covalent bonds. Contain C-C and C-H covalent bonds.

Alkanes are characterized by their tetrahedral geometry around carbon atoms.

Question 3

Describe the reactivity of alkanes

Answer 3

Generally very unreactive (except burning and substitution by chlorine).

Alkanes do not readily react with acids or bases.

Question 4

What is a substitution reaction?

Answer 4

A substitution reaction is when one atom or a group of atoms is replaced by another atom or group of atoms.

This type of reaction is common in organic chemistry, particularly with alkanes and halogens.

Question 5

What is required for alkanes to react with chlorine?

Answer 5

UV radiation- provides the activation energy for the photochemical reaction to occur.

The reaction between alkanes and chlorine is initiated by the energy from ultraviolet light.

Question 6

Write the general equation for the reaction between an alkane and a halogen

Answer 6

Alkane + halogen → haloalkane + hydrogen halide

This reaction typically requires UV light to proceed.

Question 7

Write the word equation for the reaction between ethane and chlorine

Answer 7

Ethane + Chlorine → Chloroethane + Hydrogen chloride

This illustrates a typical substitution reaction involving an alkane.