When 12.1 g of the sugar sucrose (a nonelectrolyte) are dissolved in exactly 800 g of water, the solution has a freezing point of -0.082°C. What is the molar mass of sucrose? (K_f of water is 1.86°C/m.) A) 426 g/mol B) 99.2 g/mol C) 178 g/mol D) 266 g/mol E) 343 g/mol

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Quizplus · Accepted Answer

The freezing point depression formula is ΔTf = i * Kf * m. Since sucrose is a nonelectrolyte, i = 1. ΔTf = 0.082°C, Kf = 1.86°C/m, and m = moles of solute/kg of solvent. Solving for moles of solute and using the given mass of sucrose, the molar mass is calculated to be approximately 343 g/mol.

When 121 G of the Sugar Sucrose (A Nonelectrolyte) Are Dissolved