# A mass of mercury occupies 0.95 L. What volume would an equal mass of ethanol occupy? The density of mercury is 13.546 g/mL and the density of ethanol is .789 g/mL?

##### 1 Answer

#### Explanation:

For a given substance, its density tells you the mass occupied by one **unit of volume** of that substance.

In essence, density is a measure of how well the molecules of a substance are packed in a unit of volume. In your case, the densities of the two substances are expressed in *grams per milliliter*, which means that **a unit of volume** will be

So, mercury has a density of

Your strategy here will be to use the density of mercury to find the mass that occupies

So, you will have - don't forget to convert the volume from *liters* to *milliliters*

# 0.95 color(red)(cancel(color(black)("L"))) * (10^3color(red)(cancel(color(black)("mL"))))/(1color(red)(cancel(color(black)("L")))) * overbrace("13.546 g"/(1color(red)(cancel(color(black)("mL")))))^(color(purple)("density of mercury")) = "12,868.7 g"#

The volume of ethanol that will have an equal mass is

#"12,868.7" color(red)(cancel(color(black)("g"))) * overbrace("1 mL"/(0.789color(red)(cancel(color(black)("g")))))^(color(purple)("density of ethanol")) = "16,310.1 mL"#

Rounded to two sig figs and expressed in *liters*, the answer will be

#"16,310.1"color(red)(cancel(color(black)("mL"))) * "1 L"/(10^3color(red)(cancel(color(black)("mL")))) = color(green)("16 L")#