Chemistry Question - Molarity?

Question

A solution of ethanol (C2H5OH) in water is prepared by dissolving 55.0 mL of ethanol (density = 0.79 g/cm3) in enough water to make 215.0 mL of solution.

What is the molarity of the ethanol in this solution?

Thx flying dragon.. =]

Answer 1

First find grams of ethanol: 1 ml = 1 cm^3

55ml x 0.79g/cm^3 = 43.45g

Now find moles:

43.45g/[(2 x 12.01) + (6 x 1.01) + 16.00] =

43.45g/46.08g/mol = 0.943 mole

Now find concentration:

0.943mol/0.215liter = 4.38M