Question

What is the mass percent (m/m) concentration of a solution of 10.0 g of sodium chloride in 100 g of solution?

Answer 1

`10%`

Explanation:

A solution's mass percent concentration, `"% m/m"`, is calculated by looking at how many grams of solute you get per `"100 g"` of solution.

`color(blue)(|bar(ul(color(white)(a/a)"% m/m" = "grams of solute"/"100 g of solution" xx 100color(white)(a/a)|)))`

Simply put, the solution's mass percent concentration is given by the number of parts of solute you get in `100` parts of solution, which is made up of solute and solvent.

So, if `"100 g"` of a given solution contains `"1 g"` of solute, that solution will have a `"1% m/m"` concentration.

In your case, the solution is said to contain `"10.0g"` of solute in `"100 g"` of solution, which means that its mass percent concentration will be

`"% m/m" = color(green)(|bar(ul(color(white)(a/a)color(black)(10 %)color(white)(a/a)|)))`

So, every time a problem wants you to figure out a solution's mass percent concentration, focus on determining how many grams of solute you per in `"100 g"` of solution.