# What is the mass of #"22.31 cm"^3# of zinc if the density of this metal is #"7.1 g/cm"^3# ?

##### 1 Answer

Here's what I got.

#### Explanation:

The thing to remember about a substance's **density** is that it tells you the mass of exactly **unit of volume** that substance occupies.

In this case, you know that the density of zinc is equal to

#"7.1 g cm"^(-3) " " implies " " "1 cm"^3color(white)(.)"of zinc has a mass of 7.1 g"#

Now, you know that your sample has a volume of

#(xcolor(white)(.)color(red)(cancel(color(black)("g"))))/(22.31 color(red)(cancel(color(black)("cm"^3)))) = (7.1 color(red)(cancel(color(black)("g"))))/(1 color(red)(cancel(color(black)("cm"^3))))#

This will get you

#x = 22.31 * 7.1 = 158.4#

You can thus say that your sample will have a mass of

#color(darkgreen)(ul(color(black)("mass = 158.4 g")))#

I'll leave the answer rounded to four **sig figs**, but keep in mind that you have two sig figs for the density of zinc.