Question

Are the following Physical or Chemical changes?

Mixing oil and water
Mixing Vinegar and baking soda.
Aging humans
Changing water vapor to water.
Mixing mud, sugar and water
Light breaking into seven colors when passed through a prism.

Answer 1

during physical change, there is a change in physical state of system. Physical state includes change of phase, mixing etc.

During chemical change, the identity of original compound or elements is lost. so bond are broken during chemical change and new bonds are formed.

Hence mixing oil and water, there is no chemical reaction between oil and water and hence a physical change.

Vinegar contains acetic acid and baking soda contains NaHCO3. The reaction is

CH3COOH+NaHCO3---->CH3COONa+H2O(L)+CO2 (g) .It is chemical reaction.

Aging is biochemical change which leads to thinniing of hair, decrease in muscle strength.

water vapor can be converted to water involves change in density and hence is a physical change.

sugar, mud and water are when mixed, sugr and mud are dissolved in water, so it is a physical change.

light contains all the seven colors known as VIBGYOR. So when light is passed throug prism, these seven colors are separated and is a physical change.