Chapter 3: Combustion of Fuels - Fill in the Blank Flashcards

Fill-in-the-blank flashcards covering candle flame zones, fuel concepts, and calorific values from the lecture notes.

The outermost zone of a candle flame is the __ zone.

non-luminous zone

The non-luminous zone appears __.

blue

The luminous zone is the middle zone and is __ in colour.

yellow

Incomplete combustion in the luminous zone occurs due to limited supply of __.

oxygen

The dark zone lies close to the wick and is the __ zone.

coldest

A very small blue area near the base of the flame is due to burning of __.

carbon monoxide

In the dark zone, unburnt wax vapour is present due to lack of __.

oxygen

A substance that burns in air at a moderate rate, producing a large amount of heat without leaving behind any undesirable residue is called a __.

fuel

The amount of heat energy produced on complete combustion of a unit mass of fuel in the presence of oxygen is called the __ of that fuel.

calorific value

Fuels can be classified on the basis of their source into natural or primary fuels and __ fuels.

processed or secondary

Natural or primary fuels include and .

coal and wood

Processed or secondary fuels include petrol, diesel, and __.

kerosene

Fuels can be classified on the basis of their physical state as solid, liquid, and __.

gas

Kerosene has a calorific value of about __ kJ/kg.

45,000

Petrol has a calorific value of about __ kJ/kg.

47,000

Diesel has a calorific value of about __ kJ/kg.

50,000

LPG has a calorific value of about __ kJ/kg.

55,000

Biogas has a calorific value in the range of to kJ/kg.

35,000-40,000