At solution containing 12.5 g of non-electrolyte substance in 175 g of water gave boiling point elevation of 0.70 K. Calculate the molar mass of the substance. Molal elevation constant ( K b ) for water 0.52 K k g m o l - 1 ?

Step-by-step solution

Δ T b = k b × w M × 1000 W M = K b × w × 1000 Δ T b × W M B = K b × W B × 1000 Δ T b × W A According to available data Mass of solute W B = 12.5 g Mass of solute W A = 175 g Molal elevation constant K b = 0.52 K k g m o l - 1 Elevation in boiling point temperature Δ T b = 0.70 K ∴ M = 0.52 K k g m o l - 1 × 12.5 g × 1000 0.70 K × 175 g = 53 g m o l - 1