Combustion notes

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Combustion is the name given to the

chemical reaction that we know as burning

Types of fire extinguishers:

-

Water – removes heat energy.

Use on wood, paper and textiles

- - Powder – Removes oxygen. Use

on wood, paper, textiles, flammable liquids, gas fires and electrical equipment

-

Carbon dioxide gas – removes

oxygen. Use on flammable liquids and electrical equipment

-

Foam – Removes oxygen. Use on

wood, paper, textiles and flammable liquids

Burning uses up part of the air. The part

it uses is the gas oxygen. The name for the burning reaction is combustion. A

material that burns is a fuel. When you light a fuel, you give it energy

The fire triangle is what is needed for a

fire. The three parts of the fire triangle are oxygen, heat energy and fuel

When we combust substances we react them

with oxygen

Carbon + oxygen -->

Carbon dioxide

Sulphur +oxygen --> sulphur dioxide

Monoxide – 1 oxygen

Dioxide – 2 oxygen

Trioxide – 3 oxygen

When non-metal oxides are dissolved in

water thy react with the water to form acids

Carbon dioxide + water --> Carbonic acid

Sulphur dioxide + water --> Sulphuric acid

Combustion of fuels

A fuel is a substance, which releases

energy when it is combusted. Fuels like gas, petrol and diesel all contain

carbon and hydrogen atoms. Compounds that only contain carbon hydrogen belong

to a family of compounds called hydrocarbon.

Cobalt chloride paper turns from blue to

pink if water is present

Anhydrous copper (II) sulphate, which turns

from white to blue if water is present

Fuel + oxygen -->

Carbon dioxide + water

… + O2 --> CO2 + H2O

Most liquid fuels come from crude oil. This

is usually extracted from under the sea using large drills on oil rigs

Incomplete Combustion

Sometimes there may not be enough oxygen

available for every carbon atom to make carbon dioxide

If there is not enough oxygen then we can

make a different product from combustion. We call this incomplete combustion

From this we make soot, which is particles

of carbon and carbon monoxide, a colourless gas

More atoms of carbon in a hydrocarbon fuel

= more soot