Find the volume of 1 kg of air, water and mercury.

We write down the formula for determining the mass, through the specific gravity:
m = ρ * V
3. Let us express the volume from this expression:
V = m / ρ
4. Let’s find the specific gravity of water, mercury and air from the reference book:
ρwater = 1000 kg / m³
ρmercury = 13500 kg / m³
ρair = 1.3 kg / m³
5. Substitute numerical values into formula 3, find the volumes of substances:
Vwater = m / ρwater = 1/1000 = 0.001 m³
Vmercury = m / ρmercury = 1/13500 = 0.000074 m³ = 7.4 * 10-5 m³
Vair = m / ρair = 1 / 1.3 = 0.77 m³
Answer: the volume of water 0.001 m³, mercury 7.4 * 10-5 m³, air 0.77 m³