Method

1. The mass m of the liquid can be measured using an electronic balance. To find the mass of the liquid, we subtract the mass of the empty measuring cylinder from the mass of the liquid and the measuring cylinder.
2. The volume V can be read directly from the measuring cylinder.
3. Then use the following equation to calculate density.

   ρ=

   m   V

Example 5b (ii)

1. State the equation linking density, mass and volume.
2. Calculate the density of water using the information in the diagrams below.

Answer

1. density =

   mass   volume

   or

   ρ=

   m   V

2. Step 1	List all the information in symbol form and change into appropriate and consistent SI units if required. m = 70.0 − 50.0 = 20.0g V = 20cm3 ρ = ?
   Remember: It is acceptable to use mass in g and volume in cm3 for density calculations.