There isn't a single "chemical formula" for water mixed with urea. Here's why:

* Water: H₂O

* Urea: (NH₂)₂CO

Water and urea don't react chemically to form a new compound. They simply dissolve in each other, creating a solution. The chemical formula for the solution is just the combination of the formulas:

H₂O + (NH₂)₂CO

This notation indicates a mixture of water and urea, rather than a new molecule.

Important Note: The concentration of urea in the water will determine the properties of the solution.