Question

Question #12208

Answer 1

`"8.19% v/v"`

Explanation:

A solution's volume by volume percent concentration, `"v/v %"`, tells you the number of milliliters of solute present in `"100 mL"` of solution.

You already know the number of milliliters present in `"359 mL"` of solution, so all that you need to do here is to use the known composition of the solution as a conversion factor to figure out how many milliliters of ethanol would be present in `"100 mL"` of solution.

Keep in mind that you can do this because solutions are homogeneous mixtures, i.e. they same the same composition throughout.

You will have

`100 color(red)(cancel(color(black)("mL solution"))) * "29.4 mL ethanol"/(359color(red)(cancel(color(black)("mL solution")))) = "8.19 mL ethanol"`

This means that the solution's volume by volume percent concentration is equal to

`color(darkgreen)(ul(color(black)("% v/v = 8.19% ethanol")))`

The answer is rounded to three sig figs.