mass = volume x density
Density of liquids usually is expressed in units of g/ml. If you know the density of a liquid and the volume of the liquid, you can calculate its mass. Similarly, if you know the mass and volume of a liquid, you can calculate its density.
Example Problem:
Calculate the mass of 30.0 ml of methanol, given the density of methanol is 0.790 g/ml
mass = volume x density
mass = 30 ml x 0.790 g/ml
mass = 23.7 g
In real life, you can usually look up the density of commons liquids in reference books or online.
