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 B)99.2 g C)178 g D)266 g E)343 g

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Quizplus · Accepted Answer

The freezing point depression formula is ΔTf = i * Kf * m. Since sucrose is a nonelectrolyte, i = 1. The molality (m) is calculated using the change in freezing point (ΔTf = 0.082°C) and Kf (1.86°C/m). Solving for molality gives m = 0.082 / 1.86. Using the mass of water (800 g = 0.8 kg), the moles of sucrose can be calculated. Finally, using the mass of sucrose (12.1 g) and the moles calculated, the molar mass is found to be approximately 343 g/mol.

When 121 G of the Sugar Sucrose (A Nonelectrolyte)are Dissolved in in Exactly