Question

Define the following:

1. Respiration
2. Photosynthesis
3. Combustion

Answer 1

a. Respiration:

• Respiration is a chemical process that takes place in all living beings.
• In this process, food is taken by an organism that combines with oxygen to release energy.
• This energy is utilized by the organism to carry out its various life processes. Carbon dioxide and water are the other products of the process of respiration.
• ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{s}\right)+6{\mathrm{O}}_2\stackrel{}{\left(\mathrm{g}\right)\to }6{\mathrm{CO}}_2\left(\mathrm{g}\right)+6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+\mathrm{ATP}$

b. Photosynthesis:

• Photosynthesis is the process by which green plants prepare their food with the help of carbon dioxide (${\mathrm{CO}}_2$), water (${\mathrm{H}}_2\mathrm{O}$), chlorophyll, and light.
• By using this process they convert light energy into chemical energy.

$6{\mathrm{CO}}_2\left(\mathrm{g}\right)+6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{s}\right)+6{\mathrm{O}}_2\left(\mathrm{g}\right)$

c. Combustion:

• It is the scientific word for burning. In a combustion reaction, a substance reacts with oxygen from the air.
• A combustion reaction occurs at high temperatures and transfers energy to the surroundings as light and heat.

For example: $2\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$