Question

(b) LPG is a better domestic fuel than wood.
(c) Paper, by itself, catches fire easily whereas a piece of paper wrapped around an aluminium pipe
does not
Name the unit in which the calorific value of a fuel is expressed.
6.
Explain how CO2 is able to control fires.​

Answer 1

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• (b) LPG has more calorific value and produces no pollution. So it is better domestic fuel than wood.

• (c) The ignition temperature of paper is less, so it catches fire easily. It does not catch fire when wrapped around aluminium pipe because aluminium absorbs the heat, so paper does not attain its ignition temperature.

• kJ/kg

Calorific value is the amount of energy released or produced when 1 kg of fuel burns or any other substance is burnt in the presence of oxygen and the products of combustion are cooled to STP. Its SI unit is kJ/kg.

• Carbon dioxide extinguishes work by displacing oxygen, or taking away the oxygen element of the fire triangle. The carbon dioxide is also very cold as it comes out of the extinguisher, so it cools the fuel as well.

hope it will help you!!