# Question 137db

Sep 7, 2017

${\text{0.3 g mL}}^{- 1}$

#### Explanation:

The thing to remember when looking to determine the density of a given substance is that your ultimate goal is to find the mass of exactly $1$ unit of volume of that substance.

That is, in essence, what density means--the mass of $1$ unit of volume of a substance.

In your case, the volume of the sample is given to you in milliliters, $\text{mL}$, so you can say that $1$ unit of volume would be $\text{1 mL}$.

Now, you know that $\text{24.0 mL}$ of this substance have a mass of $\text{6 g}$, so you can set up this information as a conversion factor to help you find the mass of $\text{1 mL}$ of this substance.

1 color(red)(cancel(color(black)("mL"))) * "6 g"/(24.0 color(red)(cancel(color(black)("mL")))) = "0.3 g"#

Since this represents the mass of exactly $1$ unit of volume of this unknown substance, you can say that the density of the substance will be

$\textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{{\text{density = 0.3 g mL}}^{- 1}}}} \to$ every $\text{1 mL}$ of this substance has a mass of $\text{0.3 g}$

The answer must be rounded to one significant figure, the number of sig figs you have for the mass of the sample.