20.2 g of potassium phosphate is dissolved into 650 ml of H2O

That's a statement, not a question. You want to know what?

20.2 g of potassium phosphate is dissolved into 650 ml of H2O

yes i so confuse i need to know what property is if is morality , osmolarity , boiling point or if are another property? thank you.

It's a property that it dissolves in water. One can calculate molality (note it isn't morality --these solutions have no moral character).

The definition is m = moles/kg solvent.
moles = grams/molar mass.
Solve for moles first, then substitute into m = moles/kg and solve for molality.

To determine the concentration of the potassium phosphate solution, we need to calculate the amount of potassium phosphate dissolved per unit volume of water.

First, we need to convert the volume of water from milliliters (ml) to liters (L):

650 ml ÷ 1000 = 0.65 L

Next, we can calculate the concentration of the potassium phosphate solution by dividing the mass of the potassium phosphate by the volume of water:

Concentration (in g/L) = Mass of potassium phosphate (in g) / Volume of water (in L)

Concentration = 20.2 g / 0.65 L

Concentration = 31.08 g/L

Therefore, the concentration of the potassium phosphate solution is 31.08 g/L.