posted by Anonymous on .
A solution of ethanol (C2H5OH) in water is prepared by dissolving 76.9 mL of ethanol (density 0.79 g/cm^3) in enough water to make .250 L of solution. What is the molarity of ethanol in this solution?
Calculate the mass of ethanol (m) used from the volume and the density.
Calculate the RMM for ethanol
Then use m/RMM to calculate the number of moles (M) of ethanol.
I presume the final volume is 0.250 L rather than 250 L.
The molarity is then M/0.250 L
0.79g/ml x 76.9ml = 60.7g
60.7g /46.06 = 1.3 mole
1.3/ 0.25 L = 5.2M