Calculate the molarity and the molality of an NH3 solution made up of 30.0 g of NH3 in 70.0 g of water. The density of the solution is 0.982 g/mL.

The formula for molality---> m = moles solute / Kg of solvent

the solute here is NH₃ because it's the one with less amount. which makes water the solvent.

1) let's convert the grams of NH₃ to moles using the molar mass

molar mass of NH₃ = 14.0 + (3 x 1.01) = 17.03 g / mol

30.0 g (1 mol / 17.03 g) = 1.76 mol NH₃

2) let's convert the grams of water into kilograms (just divide by 1000)

70.0g = 0.0700 kg

3) let's plug in the values into the molality formula

molality = mol / Kg---> 1.76 mol / 0.070 kg = 25.1 m