Question

Question #137db

Answer 1

`"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, `"mL"`, so you can say that `1` unit of volume would be `"1 mL"`.

Now, you know that `"24.0 mL"` of this substance have a mass of `"6 g"`, so you can set up this information as a conversion factor to help you find the mass of `"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

`color(darkgreen)(ul(color(black)("density = 0.3 g mL"^(-1)))) ->` every `"1 mL"` of this substance has a mass of `"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.