What is combustion in the context of fuels?
A
Separation of elements from fuel
B
Dissolution of fuel in water
C
Rapid chemical reaction of fuel with oxygen
D
Cooling of fuel to a solid state
Analysis & Theory
Combustion is the rapid chemical reaction of a substance (fuel) with oxygen, producing heat and usually light.
Which gas is essential for combustion to occur?
Analysis & Theory
Oxygen is required for combustion; it reacts with the fuel to produce heat and energy.
Which of the following is NOT a product of complete combustion of hydrocarbons?
Analysis & Theory
Carbon monoxide is a product of incomplete combustion, not complete combustion.
Which type of combustion occurs with sufficient oxygen and results in a clean flame?
Analysis & Theory
Complete combustion uses sufficient oxygen and produces carbon dioxide and water with a clean flame.
Which of these is a common result of incomplete combustion?
B
Production of carbon monoxide
C
Formation of only water vapor
Analysis & Theory
Incomplete combustion leads to carbon monoxide, a toxic gas, due to lack of oxygen.
What is the ignition temperature of a fuel?
A
The temperature at which the fuel melts
B
The maximum temperature a fuel can reach
C
The minimum temperature at which fuel starts to burn
D
The boiling point of fuel
Analysis & Theory
Ignition temperature is the minimum temperature at which a substance catches fire and burns.
Which of the following is a gaseous fuel used in combustion?
Analysis & Theory
LPG (Liquefied Petroleum Gas) is a gaseous fuel widely used for cooking and heating.
What is the calorific value of a fuel?
B
The amount of oxygen needed to burn it
C
The amount of heat energy produced per unit mass
Analysis & Theory
Calorific value is the amount of heat energy released on complete combustion of 1 kg of fuel.
Which fuel has the highest calorific value among the following?
Analysis & Theory
Hydrogen has the highest calorific value among common fuels.
What is the effect of excess air in combustion?
B
Decreases flame temperature
D
Creates more carbon dioxide
Analysis & Theory
Excess air cools the flame and reduces combustion efficiency by absorbing heat.