Question #a69e3

1 Answer
Stefan V.
May 5, 2016

"30% m/m"

Explanation:

A solution's percent concentration by mass, "%m/m", essentially tells you how many grams of solute you get in "100 g" of solution.

This means that in order to find a solution's percent concentration by mass, you must determine how many grams of solute you have in "100 g" of solution.

In your case, the solution is said to contain "90 g" of calcium iodide, "CaI"_2, which is your solute, and have a total mass of "300 g".

This means that "100 g" of solution will contain

100 color(red)(cancel(color(black)("g solution"))) * "90 g CaI"_2/(300color(red)(cancel(color(black)("g solution")))) = "30 g CaI"_2

So, if "100 g" of solution contains "30 g" of solute, it follows that its percent concentration by mass will be equal to

"% m/m" = color(green)(|bar(ul(color(white)(a/a)"30%"color(white)(a/a)|)))

Related questions
See all questions in Percent Concentration
Impact of this question
1814 views around the world
You can reuse this answer
Creative Commons License