Question

Please help me understand!..If you have 100.0mL of a 30.0% aqueous solution of ethanol, what volume of water is in the solution?

Answer 1

Is that 30.0% v/v or some other unit?
If v/v, that means 30.0 mL ethanol in enough water to make 100 mL solution. How much water is that? I don't know since the volume of ethanol and the volume of H2O are not additive. (Meaning that 50 mL ethanol and 50 mL water equals approximately 95 mL total volume).

Answer 2

70 ml of water

Answer 3

30 mL ethanol + 70 mL H2O does not equal 100 mL solution. It will be close but it will be less than 100 mL.