The molality of an aqueous NaBr solution is 250 m What is th

The molality of an aqueous NaBr solution is 2.50 m. What is the mass percent of NaBr?

(NaBr molar mass = 102.9 g/mol)

Answer is 20.5% - just need the steps - thanks!

Solution

so we know that 2.5 moles are present in 1 kg of the solvent(i.e. water)

so mass of NaBr=102.9*2.5

=257.25

so net mass of the solution=1000+257.25

=1257.25

so % of NaBr=257.25*100/1257.25

=20.5 %