You are right about using 675 grams of water, but you are wrong about the g/L concentration. Volume changes, so it is not 0.675 L . The only way to find out the final volume is to either measure it, or use experimental density of the solution of a given concentration found in data tables (1.0883 g/mL for 32.5% urea).

I need to find the answer to the question: how much gram of Urea do you need to add to 1L off water to get a 32,5% solution. So like the methode of previous post:

Add 481,48g of Urea to 1000g of water to get a solution of 32,5 w/w%.

But why can't i say that the concentration of Urea in the water is equal to 481,48g/L? Since i dissolve the urea in water?

Anyways using the density: total solution mass = 1481,48g this solves to a volume of 1367,52 mL.

Is the concentration now of Urea in the solution now equal to: 481,48g / 1367,52 mL = 352,08 g/L?

But now i have 2 concentrations. You see my problem?

I want the concentration since it's easier to work with; since you can just read that mass you need to add to 1L of water

Hope you can help me