The simple formula for density is
where d is density, m is mass and v is volume. A simple problem to demonstrate this would be
What is the density of a liquid if 30.0 mL of the liquid has a mass of 45.0 g?
The formula for density can, of course, be rearranged algebraically to allow us to solve for mass (given density and volume) or to solve for volume (given density and mass), as the following problems demonstrate.
What is the mass of 2.54 mL of a liquid with a density of 0.77 g/mL?
What is the volume of 16.8 g of a solution with a density of 1.44 g/mL?