CBSE Class 8 Science - Combustion and Flame

CBSE Class 8 Science - Combustion and Flame 

Describe how the use of compressed natural gas (CNG) in automobiles has contributed to the reduction of pollution in our cities.

In the following ways, the use of compressed natural gas (CNG) in cars has resulted in considerable reductions in pollution in our cities:

• Compressed natural gas (CNG) is a clean fuel that emits no smoke when burned, unlike other petroleum-based fuels such as gasoline and diesel.
• Petroleum fuel is used to power autos.
• Unburned carbon particles, as well as carbon monoxide (CO), a dangerous and destructive gas, are released into the air when fuel is burned.
• CO produces headaches, dizziness, and other symptoms.
• CNG burns cleanly and leaves no toxic behind.

Make a list of the circumstances in which combustion occurs.

The following are the conditions that lead to combustion:

• The presence of oxygen aids in burning.
• Getting the ignition temperature you want.
• There is flammable material present.

Check out the Comparison between LPG and wood as fuels

 Class 8 Science Practice Worksheet

1. Fill in the blanks:

• Burning of _______ and _______ causes pollution of air.
• ________ is a liquid fuel, which is used in homes.
• Before the fuel starts burning, it must be heated to its _________.
• Oil-fueled fires are uncontrollable by _________.

2. State True or False:

• Because it is made up of oily carbon, soot created by burning is not toxic to us.
• CNG means ‘Compressed Natural Gas’.
• Combustion requires the presence of air.
• The wick in a candle serves as the source of heat and light.