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What is the freezing point of a 50% by volume ethanol solution? Assume water is the...

What is the freezing point of a 50% by volume ethanol solution? Assume water is the solvent.

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Answer #1

assume densities are additive

density of ethanol = 0.789 g/ml

density of water = 1 g/ml

D solution = 0.5*1 + 0.5*0.789 = 0.95 g/ml

assume

m = 100 g of solution

V = m/D = 100 /0.95 = 105.263 ml

thjen

105.263*0.5 = 52.6315 ml of ethanol

mass of ethanoil = 52.6315*0.789 = 41.52 g of ethanol

mol = mass/MW = 41.52/46 = 0.90260 mol of ethanol

mass of solvent = 100-41.52 = 58.48 g = 58.48/!000 = 0.05848 kg

dTf = -KF*m

m = molality = mol solute / kg solvnet =0.90260 / 0.05848 = 15.43433 molal

dTf = -1.86*15.43433 = -28.70

Tf = -28.70°C

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