# A piece of PVC pipe displaces 60 mL when placed in a container of water. If the pipe has a mass of 78 g, what is its density?

May 27, 2018

#### Answer:

Refer to the explanation.

#### Explanation:

"density"=("mass")/("volume")

The $\text{60 mL}$ of displaced water is the volume of the PVC pipe. Since the PVC pipe is a solid, we can use the equality $\text{1 mL}$$=$$\text{1 cm"^3}$ to convert $\text{60 mL}$ to $\text{60 cm"^3}$.

60color(red)cancel(color(black)(1"mL"))xx("1 cm"^3)/(1color(red)cancel(color(black)("mL")))="60 cm"^3"

$\text{density of PVC pipe"=("78 g")/("60 cm"^3)="1.3 g/cm"^3}$, which should be rounded to $\text{1 g/cm"^3}$ which has one significant figure because $\text{60 mL}$ has one significant figure.