Question

describe an experiment that you could carry at home to show that masses are or are not additive. Describe an experiment to show that volumes are or are not additive. Explain how the first shows that masses are additive while the second shows that volumes can be either additive or non-additive

Answer 1

1. To show that mass are additive take a 50 gm of sugar and mix it with 50 gm of salt. Now on measuring the mass of mixture we get 100 gm this shows that mass are additive.
2. Now take 10 ml of oil and mix it with 10 ml of water. On measuring the resulting solution we get 20 ml of mixture. This shows volume are additive.
3. Now take 10 ml of water and mix it with 10 ml of any alcohol. the resulting mixture will not be equal to 20 ml.

The first shows that mass are additive and the on the basis of 2 and 3 the volume can be either additive or non additive. This is because volume of mixture depend on the interactions of the liquids' molecules. Thus if the molecules of one species dissolve completely in another thus the total volume remains constant or it will not increase. The particles of solute specie occupy the void spaces in the solvent molecule. Thus the volume may increase if the two liquid particles does not interact with each other and may remain constant if the liquid particles interact with each other.

This shows that the masses are additive while the volumes can be either additive or non-additive