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com/ibiscms/mod/ibis/view.phpid-4961241 select then , and drag to the Favorites Bar folder. Or import from another browser. Import favorites Learning ing 2/12/2018 08:00 AM O 40,100 Score Gradeboo Print Caculator-Porodic Table Question 6 of 20 Sapling Learning Map a A solution is made by mixing 30.0 mL of ethanol, CaHeO, and 70.0 ml of water. Assuming ideal behavior, what is the vapor pressure ofthe solution at 20 ? Values at 20 Number Liquid (gml ethanol 0.789 water 0.998 Vapor Pressure, P Tom) 43.9 7.5 Torr OPrevas Gve up & View Solton·Check Answer Ext Next rchExplanation / Answer
Given
30 ml of ethanol
70 ml of water
Mass of water = 70 ml * 0.998 g/ml (density) = 69.86 g
mass of ethanol = 30 ml * 0.789 g/ml = 23.67 g
Molar mass of water = 18 g/mol
Molar mass of ethanol = 46 g/mol
No. of moles of water = mass / molar mass = 69.86 g / 18 g/mol = 3.88 moles
No. of moles of ethanol = 23.67 g / 46 g/mol = 0.52 moles
Mole fraction of water = Moles of water / total no of moles = 3.88 / (3.88 + 0.52) = 0.882
Mole fraction of ethanol = 1 - 0.882 = 0.118
Roault's law
P = xAPA + xBPB
Total vapor pressure = 0.882 * 17.5 + 0.118 * 43.9 = 20.62 torr Answer
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