Density Basics

Density is a ratio of mass to volume of a substance. Density can be used to determine the identity of a substance.

Density (D) = Mass (M)/Volume (V)

The most common unit for density is grams/cm³, but this can also be grams/mL. The cm³ is equal to 1mL and is a common conversion based that relates back to water.

Solve each problem provided the given information.

1. If an object has a mass of 30g and a volume of 15g, what is its density?
2. If a piece of aluminum has a volume of 35ml and a mass of 91g, what is its density?
3. Aquamarine, the birth stone of March, has a density of 2.70g/cm³. If a stone is 10cm x 2cm x 1cm, what is the mass of the stone?
4. A piece of gold has a density of 19.3g/cm3. It was measured to have a mass of 32g, so what is the volume of the piece?

The next problem is based on a set of unknowns as shown in the picture.

We know the identities of the items based on the packaging and that information is provided below.

Package contains:

Copper Density = 8.96 g/cm³

Iron Density = 7.87 g/cm³

Zinc Density = 7.14 g/cm³

Aluminum Density = 2.60 g/cm³

Unfortunately, we needed to take measurements to determine match the information with the blocks. The following information was collected. The blocks are 20mm cubes.

Block A has a mass of 62.96g.

Block B has a mass of 57.12g.

Block C has a mass of 20.80g.

Block D has a mass of 71.68g.

Calculate the densities and identify the composition of the blocks.