# Question #a54ac

##### 1 Answer

#### Explanation:

You know that in order to find the **density** of a substance, you need to know two things

thevolumeof a given sample of said substancethemassof this sample

The problem tells you that **volume** of the sample.

Now, in order to find its *mass*, you must use the mass of the empty flask and the mass of the flask + sample. You can say that **after** you fill the empty flask with the sample of substance

#color(blue)(ul(color(black)(m_"flask + sample" = m_"flask" + m_"sample")))#

This means that

#m_"sample" = m_"flask + sample" - m_"flask"#

In your case, this will give you

#m_"sample" = "24.461 g" - "14.824 g"#

#m_"sample" = "9.637 g"#

So now you know the volume of the sample **and** its mass. In order to find its **density**,

#rho = "9.637 g"/"10.00 mL" = color(darkgreen)(ul(color(black)("0.9637 g mL"^(-1))))#

The answer is rounded to four **sig figs**.

Notice that this is equivalent to determining the mass of **one unit of volume**, which would be

#1 color(red)(cancel(color(black)("mL"))) * overbrace("9.637 g"/(10.00color(red)(cancel(color(black)("mL")))))^(color(blue)("what you know about the sample")) = "0.9637 g"#

This means that the density of the substance, which by definition is the mass of one unit of volume of said substance, will once again be

#rho = color(darkgreen)(ul(color(black)("0.9637 g mL"^(-1)))) -># this tells you thatevery#"1 mL"# of substance#"A"# has a mass of#"0.9637 g"#