Answer:
- melting ice is a physical change
- souring of milk is a chemical change
- digesting food is a chemical change
- evaporating water is a physical change
Explanation:
A chemical change involves formation of new product and is irreversible, while physical change may involve the formation of new products and is easily reversible.
Physical Changes are described below
- Ice on melting forms water, that can be refrigerated to yield ice again
- water on evaporation during heating yields steam that can be condensed to yield water again.
Chemical change
- souring of milk involves bacteria oxidation of chemicals in the milk that changes its composition, smell, and taste; fresh milk CANNOT be obtained again
- food digestion involves mechanical breaking by teeth, stomach walls and several enzyme actions to yield glucose, amino acids etc. It cannot be reversed to whole food again
