n(H2O) = 10 mol
M(H2O) = 2 * 1 + 16 = 18 g/mol
m(H2) = M * n = 18 * 10 = 180 g
m(раствора) = 180 + 20 = 200 g
w%вещ = 20 / 200 * 100 = 10%
n(H2O) = 10 mol
M(H2O) = 2 * 1 + 16 = 18 g/mol
m(H2) = M * n = 18 * 10 = 180 g
m(раствора) = 180 + 20 = 200 g
w%вещ = 20 / 200 * 100 = 10%