How many moles of sugar was added to 82.90 g of ethanol to change the freezing point of ethanol by 2.750 c
F.P of ethanol = -116.2 c
Kf of ethanol = -1.990 c kg/mol
How many moles of sugar was added to 82.90 g of ethanol to change the freezing point of ethanol by 2.750 c?
2021-02-23 2:41 pm
回答 (1)
2021-02-23 4:31 pm
✔ 最佳答案
Sugar dissolves in ethanol in molecular form. van't Hoff index, i = 1Kf of ethanol = -1.990 °C kg/mol
ΔTf = -2.750 °C
ΔTf = i m Kf
-2.750 = 1 × m × (-1.990)
Molality, m = 1.382 mol/kg
Moles of sugar = (1.382 mol/kg) × (82.90/1000 kg) = 0.1146 mol
收錄日期: 2021-04-25 13:43:15
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