Respuesta :

Density can be defined as the mass of substance per unit volume. 
d = m/v

Where d is the density, m is the mass and v is the volume.

d = 0.84 g/mL
m = 321 g
v = ?

From substitution,
     0.84 g/mL = 321 g / v
                  v = 321 g / 0.84 g/mL
                  v = 382 mL
                  v = 0.38 L

Hence, the volume of 321 g of liquid is 
0.38 L.