Question

The substance that packs ___________ number of molecules in a unit volume is said to be less dense.

Answer 1

1. Density is the measurement of how tightly a material is packed together. It is defined as the mass per unit volume.
2. $Density=\frac{mass}{volume}$
3. In a substance, lesser molecules means lesser mass.
4. Density of body depends on mass, so less mass leads to lesser density.

Hence, The substance that packs less number of molecules in a unit volume is said to be less dense.