The release of sulfur dioxide and nitrogen oxides into the air.
Explanation:
Your question does not add any specific guidelines for answers so I'll just cover the basics.
Sulfur dioxide (or SO2) and nitrogen oxides (NOX) are released into the air from powerplants after fossil fuel is burnt. These gases are admitted into the atmostphere, and get carried by air currents. They react with other chemicals and create sulfuric and nitric acids. They then mix with water before falling to the ground in precipitation, i.e. acid rain.
Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents. The SO2 and NOX react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground.
When a substance undergoes a physical change, its composition remains the same despite its molecules being rearranged.
Physical change is a temporary change.
A Physical change affects only physical properties i.e. shape, size, etc.
A physical change involves very little to no absorption of energy.
Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. .
In a physical change, no new substance is formed.
Physical change is easily reversible i.e original substance can be recovered.
Chemical Change
When a substance undergoes a chemical change, its molecular composition is changed entirely. Thus, chemical changes involve the formation of new substances.
.A chemical change is a permanent change.
Chemical change both physical and chemical properties of the substance including its composition
During a chemical reaction, absorption and evolution of energy take place.
A few examples of chemical change are digestion of food, burning of coal, rusting, etc.
A chemical change is always accompanied by one or more new substance(s).
Chemical changes are irreversible i.e. original substance cannot be recovered.