Question

4. Define the following terms:-
a) Law of conservation of mass
b) buoyancy
c) density with units.
d) Pure substance.​

Answer 1

a) Law of conservation of mass:-

In a chemical reaction, mass can neither be created nor destroyed. (This law was given by Lavoisier.)

b) Bouyancy:-

An upthrust given by a fluid to the particle which is partially or fully submerged in it. (It was discovered by Archimedes.)

c) Density with units:-

Density of a particle implies mass per unit volume of it. It has several units. Like the CGS is g/cm³, MKS or SI is kg/m³. (It is denoted by a greek letter 'rho'.)

d) Pure substances:-

Substances which are completely made of similar kind of particles which have similar chemical properties are termed pure substances. (Iñstances are elements and compounds.)