# An empty vial weighs 50.90 g. If the vial weighs 439.31 g when filled with liquid mercury (d = 13.53 g/cm^3), what volume of mercury is in the vial?

##### 1 Answer

#### Explanation:

Your strategy here will be to use the mass of the *empty vial* and the mass of the vial *when filled with mercury* to find the **mass of mercury** added to the vial.

Once you know the mass of mercury, you can use its **density** to find the **volume** of mercury present in the vial, i.e. the volume of the vial.

So, you know that the vial + mercury has a mass of

#"vial " + " mercury" = "439.31 g"#

The mass of the vial is

#"vial " = " 50.90 g"#

This means that the mass of the mercury will be

#"mercury" = "439.31 g" - "50.90 g" = "388.41 g"#

Now, you know that mercury has a density of

In your case, the volume of the sample will be

#388.41 color(red)(cancel(color(black)("g"))) * "1 cm"^3/(13.53color(red)(cancel(color(black)("g")))) = color(green)(bar(ul(|color(white)(a/a)color(black)("28.71 cm"^3)color(white)(a/a)|)))#

The answer is rounded to four **sig figs**, the number of sig figs you have for the mass of the empty vial.