Question #bc6af

2 Answers
Mar 24, 2017

"10. mL H"_2"O"_2

Explanation:

A solution's volume by volume percent concentration, "v/v %", is a measure of the number of milliliters of solute present for every "100 mL" of solution.

In other words, the volume by volume percent concentration tells you how many milliliters of solute you would have if you were to pick a "100-mL" sample of a given solution.

In your case, you know that the solution has a 3.0% volume by volume concentration, which means that every "100 mL" of this solution contain "3.0 mL" of hydrogen peroxide, the solute.

Now, solutions are homogeneous mixtures, which means that the same the same composition throughout. This allows you to use the percent concentration as a conversion factor to determine how many milliliters of hydrogen peroxide you'd get in "348 mL" of solution.

348 color(red)(cancel(color(black)("mL solution"))) * overbrace(("3.0 mL H"_2"O"_2)/(100color(red)(cancel(color(black)("mL solution")))))^(color(blue)("= 3.0% v/v")) = "10.44 g H"_2"O"_2

The answer must be rounded to two sig figs, the number of sig figs you have for the percent concentration.

Therefore, you will have

color(darkgreen)(ul(color(black)("volume H"_ 2"O"_ 2 = "10. mL")))

Mar 24, 2017

10.44mL H_2O_2

Explanation:

The antiseptic H_2O_2 solution is 3.0% (v/v). This means that for every 100mL of the antiseptic solution, you have 3mL of the solute, H_2O_2.

3% (v/v) is the same thing as writing as (3mL (H_2O_2))/(100mL(solution)) * 100% so,

If for every 100mL of soln you have 3mL of H_2O_2, then for 348 mL you would have:

(3mL(H_2O_2) )/(100mL(solution)) = (x mL)/(348mL (solution))

cancel348mL (solution)*(3mL (H_2O_2))/(cancel100mL(solution)) = x mL (H_2O_2)

Answer: 10.44mL H_2O_2