Question

What is the volume of a rock with a density of 45 g/mL and a mass of 855 grams?

Your answer must have units

Answer 1

19 mL

Explanation:

You want the volume of a rock with density 45 g/mL and mass of 855 g.

Volume

The units of density are mass per volume, so we can find the volume by dividing the mass by the density. The units basically tell you how to work the problem.

`\frac{855\text{ g}}{45\text{ g/mL}}=(855)/(45)\,\frac{\text{g$\cdot$mL}}{\text{g}}=\boxed{19\text{ mL}}`

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Additional comment

Sometimes we like the volumes of things that aren't liquid to be expressed in cubic units. 1 mL = 1 cm³, so the volume could be described as 19 cm³.