What is the percent by mass of KBr if 58.2 grams are dissolved in 344 grams of water?
The idea here is that you need to determine how many grams of potassium bromide will be present for every
If you dissolve
#"58.2 g + 344 g = 402.2 g"#
So this solution contains
#100. color(red)(cancel(color(black)("g solution"))) * "58.2 g KBr"/(402.2 color(red)(cancel(color(black)("g solution")))) = "14.5 g KBr"#
You can thus say that the solution's percent concentration by mass is equal to
#color(darkgreen)(ul(color(black)("% m/m = 14.5% KBr")))#
The answer is rounded to three sig figs, the number of sig figs you have for your figures.
The percent by mass of
The given mass of the solute
The mass of the solution is
Plug in the known values and solve.