Definitions

Question 1

Define organic chemistry

Answer 1

The study of the compounds of carbon

Question 2

Define hydrocarbons

Answer 2

A compound that contains carbon and hydrogen only

Question 3

Define fossil fuels

Answer 3

Fuels that were formed from the remains of plants and animals that lived millions of years ago

Question 4

Define a saturated compound

Answer 4

A compound in which there are only single bonds between the atoms in the molecule

Question 5

Define the a homologous series
(5)

Answer 5

A series of compounds of similar chemical properties

Showing gradations in physical properties

Having a general formula for its members

Each member having a similar method of preparation

Each member differing from the previous member by a (CH2) unit

Question 6

Define structural isomers

Answer 6

Compounds with the same molecular formula but different structural formulas

Question 7

Define an unsaturated compound

Answer 7

A compound which contains one or more double or triple bonds between the atoms in the molecule

Question 8

Define an aliphatic compound

Answer 8

An organic compound that consists of open chains of carbon atoms and closed chain compounds (rings) that resemble them in chemical properties

Question 9

Define an aromatic compound

Answer 9

A compound that contains a benzene ring structure on their molecules

Question 10

Define auto-ignition

Answer 10

The premature ignition of the petrol-air mixture before ignition of the mixture by a spark takes place

Question 11

Define octane number

Answer 11

The octane number of a fuel is a measure of the tendency of the fuel to resist knocking

Question 12

Define heat of formation

Answer 12

The heat of formation of a compound is the heat change that takes place when one mole of a compound in its standard state is formed from its elements in their standard states

Question 13

Define heat of reaction

Answer 13

Heat of reaction is the heat change when the numbers of moles of reactants indicated in the balanced equation for the reaction react completely

Question 14

Define heat of combustion

Answer 14

The heat of combustion of a substance is the heat change when one mole of the substance is completely burned in excess oxygen

Question 15

Define kilogram calorific value

Answer 15

The kilogram calorific value of a fuel is the heat energy when 1kg of the fuel is completely burned in oxygen

Question 16

Define bond energy

Answer 16

It is the average energy required to break one mole of a particular covalent bond and to separate the neutral atoms completely from each other

Question 17

Define catalytic cracking

Answer 17

Catalytic cracking is the breaking down of long-chain hydrocarbon molecules by the action of heat and catalysts into short-chain molecules for which there is greater demand.