A drop of acetone (nail polish remover) has a mass of 35 mg and a density of 0.788 g/cm3. what is its volume in cubic centimeters?

The density of any given substance or object is the ratio of its mass to its volume. In equation,

ρ = m/V, where ρ is density, m is mass and V is volume

We are given with ρ=0.788 g/cm³ and m=35 mg. First thing to do is, make sure your units are consistent. We want a volume in terms of cm³. Our density is in terms of g/cm³. However, our mass is in mg. So, let's convert mg to g. In every 1 gram, there is 1000 mg.

m = 35 mg * (1 g/1000 mg) = 0.035 g

Then, we can already use the formula for density:

0.788 g/cm³ = 0.035 g / V

V = 0.0444 cm³