What mass in grams of a molecular substance (molar mass = 50.0 g/mol) must be added to 500 g of water to produce a solution that boils at 101.56°c?

M(substance) = 50,0 g/mol.
m(H₂O) = 500 g ÷ 1000 g/kg = 0,5 kg.
Tb(solution) = 101,56°C.
Tb(H₂O) = 100°C.
ΔTb = 101,56°C - 100°C = 1,56°C.
The boiling point elevation is directly proportional to the molality of the solution according to the equation: ΔTb = Kb · b.
1,56°C = 0,512°C·kg/mol · b.
b = 3,046 mol/kg.
n(substance) = 3,046 mol/kg · 0,5 kg = 1,523 mol.
m(substance) = 1,523 mol · 50 g/mol = 76,15 g.

The answer would be