# Question #a9226

##### 1 Answer

#### Explanation:

The **density** of a substance tells you the mass of exactly **one unit of volume** of that substance. Simply put, the density of a substance provides you with a *conversion factor* that can be used to go from mass to volume or vice versa.

In this case, the liquid is said to have a density of **for every**

#color(darkorange)("0.775 g")color(white)(.) color(blue)("mL"^(-1)) -> color(darkorange)("0.775 g") color(white)(.) "for every" color(white)(.) color(blue)("1 mL") color(white)(.)"of liquid"#

Now, you know that your sample has a volume of

#color(blue)(ul(color(black)("1 mL" = "1 cm"^3)))#

You can thus use the density of the liquid as a conversion factor to find the mass of the sample

#25 color(red)(cancel(color(black)("cm"^3))) * (1color(red)(cancel(color(black)("mL"))))/(1color(red)(cancel(color(black)("cm"^3)))) * "0.775 g"/(1color(red)(cancel(color(black)("mL")))) = color(darkgreen)(ul(color(black)("19 g")))#

The answer is rounded to two **sig figs**, the number of sig figs you have for the volume of the sample.