Question

Question #863ff

Answer 1

`"12.0 g NaCl"`

Explanation:

The problem provides you with the solution's percent concentration by mass, which essentially tells you how much solute you for every `"100 g"` of solution.

In this case, a `"12.0%` sodium chloride solution will contain `"12.0 g"` of sodium chloride, which is your solute, for every `"100. g"` of solution.

That is to say that you can make this solution by dissolving `"12.0 g"` of sodium chloride in `"88.0 g"` of water. The total mass of the solution will be

`m_"solution" = overbrace("12.0 g")^(color(red)("solute")) + overbrace("88.0 g")^(color(blue)("solvent")) = "100. g"`

Since the solution contains `"12.0 g"` of sodium chloride in `"100. g"` of water, its percent concentration by mass will be `12.0%`.