Question

5. Use the formula that states the mass-to-volume ratio of a substance to solve the following:

(a) what is the density of a substance that has a mass of 7.9 g and a volume of 4.3 cm³?

(b) what is the mass of a substance that has a density of 8.9 g/cm³ and a volume of 5 cm³?

(c) what is the volume of a substance that has a density of 1.25 g/mL and a mass of 150 g?

Answer 1

Step-by-step explanation:

Part A

Density equals mass divided by volume. The units for density are g/cm³ or g/mL. Note that 1 cm³ = 1 mL.

d = m/v

Substitute the mass and the volume into the equation and then divide the bottom number into the top number.

d = 7.9 g/4.3 cm³ = 1.8 g/cm³

Part B

The density of a substance can be used as a conversion factor to find either the mass of the substance or the volume of the substance.

5 cm³ x 8.9 g/cm³ = 45 g

Note that cm³ units cancel and you are left with grams.

Part C

We will use the density of the substance to find the volume of the substance.

150 g x 1 mL/1.25 g = 120 mL

Note that you can invert density so the units of g cancel and you are left with mL.