chemistry help please?

Question

A solution is prepared by dissolved 15.0 grams of NH3 in 250 grams of water. The density of the resulting solution is 0.974 g/ml. Calculate the molality and molarity of NH3 in the above solution. Show work.

how do solve this problem?
thanks

Answer 1

The molality is simply moles of solute in Kg. of solvent

Convert the 15.0 g of NH3 to moles and divide by the kg of water (convert the ml of water at 1 g/ml) to get molality.

The molarity is trickier. After mixing the 2 components you now have 265 grams of solution. Use the density to calculate ml or liters of that the solution.

Use the same moles as in the first part, but now divide by the total liters to get molarity