Practice Questions for Atoms and Molecules Science Class 9

According to the law of conservation of mass, during any chemical change, the total mass of the _________.

The quantity of matter present in an object is called its _________.
The chemical formula of magnesium chloride is
Atoms of which isotopes are used as a standard to compare the masses of different atoms of elements
All samples of carbon dioxide contain carbon and oxygen in the mass ratio of 3 : 8. This is in agreement with the law of ____________.

The word "mole" was introduced by __________.