To 300ml. a solution of maple syrup with a mass fraction of sugar 20% (solution density 1.2 g / ml)

To 300ml. a solution of maple syrup with a mass fraction of sugar 20% (solution density 1.2 g / ml) was added 40 g of sugar. Determine the mass fraction (%) of sugar in the new syrup?

Given:
V1 solution (sugar) = 300 ml
ω1 (sugar) = 20%
ρ1 solution (sugar) = 1.2 g / ml
m2 (sugar) = 40 g

To find:
ω3 (sugar) -?

Decision:
1) m1 solution (sugar) = ρ1 solution (sugar) * V1 solution (sugar) = 300 * 1.2 = 360 g;
2) m1 (sugar) = ω1 (sugar) * m1 solution (sugar) / 100% = 20% * 360/100% = 72 g;
3) m3 (sugar) = m1 (sugar) + m2 (sugar) = 72 + 40 = 112 g;
4) m3 solution (sugar) = m1 solution (sugar) + m2 (sugar) = 360 + 40 = 400 g;
5) ω3 (sugar) = m3 (sugar) * 100% / m3 solution (sugar) = 112 * 100% / 400 = 28%.

Answer: The mass fraction of sugar is 28%.