6 Ethanol C2H6O is a substance used in the manufacture of al

6. Ethanol, C2H6O, is a substance used in the manufacture of alcoholic beverages. Ethanol is a water-soluble liquid with a density of 0.790 g/mL at 25 °C. Calculate the molarity of a solution of ethanol made by dissolving 90.0 mL of ethanol at 25 °C in enough water to make 500 mL of solution. a) The solution is 0.00309 molar in ethanol. b) The solution is 3.09e-06 molar in ethanol. c) The solution is 95.2 molar in ethanol. d) The solution is 3.09 molar in ethanol. e) The solution is 1.93 molar in ethanol.

Solution

6. Density = Mass / volume

Mass of Ethanol = Density of ethanol * Volume of ethanol

= 0.790g/mL * 90mL = 71.1g

Molar mass of ethanol = 46.07g/mol

Moles of ethanol = 71.1g/46.07g/mol = 1.543moles

Molarity of ethanol = moles of ethanol/Volume of soln in L

= 1.543moles/0.5L

Molarity = 3.09 molar in ethanol