A piece of brass of volume 30 cm³ has a mass of 252 g. Find the density of brass in:

(i) g cm^-3

(ii) kg m^-3

Mass = 252 g
Volume = 30 cm^-3
Density = ?

(i) $\text{Density} = \dfrac{\text{Mass}}{\text{Volume}} \\[1em] \text{Density} = \dfrac{\text{252}}{\text{30}} = 8.4 \text{g cm}^{-3}$

So, Density = 8.4 g cm^-3.

(ii) 1 g cm^-3 = 1000 kg m^-3
8.4 g cm^-3 = 8.4 x 1000 = 8400 kg m^-3

So, Density = 8400 kg m^-3.