Question

The density of a 19.0% by mass ethylene glycol ({\rm{C}}_2 {\rm{H}}_6 {\rm{O}}_2 ) solution in water is 1.04 g/mL. find the molarity of the solution

Answer 1

I'll help you out because this is good practice...I'm studying the same thing in my chemistry class.
Molarity is moles solute per liter solution. E. glycol is 36g/mol. Divide the density by this to get 2.89mol/mL. That's you're mols solute. Pretend the whole solution is 1000mL. 19% of that is e. glycol, so 190mL of that is your solute. The volume of solvent is 810mL.
Divide 2.89 by .810L to get your molarity.

Honestly, this is mostly a guess. Don't trust this method...did you find a better method?