Posted by Fai on Sunday, August 19, 2012 at 8:07pm.
What is the molarity of 100ml of ethanol dissolved in 1.5L of water? Ethanol has a specific of 0.789, and its molecular weight is 46g/mol.
My calculation
0.789 x 1.5L = 1.1184
1.184/46g = 0.025
x= 26M
I am not sure answer. Pls help

chemistry  DrBob222, Sunday, August 19, 2012 at 9:00pm
M = mols/L soln
How much does 100 mL ethanol weigh? That is m = v x d = 100 mL x 0.789 g/mL = 78.9g and that is 78.9/46 = 1.715 mols.
So 1.715 mol/L soln is molarity. Your problem has the ethanol dissolved in 1.5 L so the final solution is 1.5L + 0.100L IF (and it's a big if) the volumes are additive. They aren't but the only way we can finsh the problem is to assume they ARE additive. Therefore, 1.5L H2O + 0.100 L ethanol adds to make 1.6L of solution if the solutions are additive.
Then 1.715/1.6L = ? molarity.