Question

If a sample of copper with a density of 8.90 g/cm3 displaces 13.0 mL of water when placed in a beaker, what is its mass?

Answer 1

When a body is partially or totally immersed in a fluid it displaces fluid with a volume equivalent to its volume.
The volume of water displaced is equal to the volume of copper
Therefore; mass of copper will be; 
= 8.9 × 13 = 115.7 g
The mass of copper is 116 grams