Question

A solution containing 40 gram of common salt is 320 gram of water calculate the concentration in terms of the solution

Answer 1

Mass (solute) = 40 gram

Mass (solvent) = 320 gram

Mass (solution) = Mass (solute) + Mass (solvent)

                        = 40 gram + 320 gram

                        = 360 gram

∴ Mass % (solution) = [ Mass (solute)/Mass (solvent)] × 100

                                = [40/360] × 100

                                = 11.1 %

Answer 2

$\frac{mass \: of \: solute}{mass \: of \: solution} \times 100 = concentration \: by \: mass$
$\frac{40}{320 + 40} \times 100$

$= \frac{40}{360} \times 100$
$= \frac{1}{9} \times 100 = 11.111$