Question #651e9

1 Answer
Stefan V.
Dec 11, 2015

V_(C_3H_8O) = "330 mL"

Explanation:

A solution's percent concentration by volume is defined as the volume of the solute, which in your case is isopropyl alcohol, "C"_3"H"_8"O", divided by the total volume of the solution, and multiplied by 100.

color(blue)("% v/v" = "volume of solute"/"volume of solution" xx 100)

In your case, rubbing alcohol is said to contain "70. %v/v" isopropyl alcohol. What that means is that every "100 mL" of rubbing alcohol will contain "70. mL" of isopropyl alcohol.

You're interested in finding out how much isopropyl alcohol you get in "473 mL" of rubbin alcohol, so you can say that

473 color(red)(cancel(color(black)("mL rubbing alcohol"))) * ("70. mL C"_3"H"_8"O")/(100color(red)(cancel(color(black)("mL rubbing alcohol")))) = "331.1 mL C"_3"H"_8"O"

You need to round this off to two sig figs, the number of sig figs you have for the percent concentration by volume

V_(C_3H_8O) = color(green)("330 mL")

Related questions
See all questions in Percent Concentration
Impact of this question
10124 views around the world
You can reuse this answer
Creative Commons License