Density=1.25gL
Weightingrams(sodium)=92grams
Weightofsolvent=1Kg
molality=NumberofmolesofsoluteWeightofsolventinKg
Numberofmolesofsolute(sodium)=WeightingramsMolecularweight=9223=4moles
molality=41=4
If the density of some lake water is 1.25 g mL−1 and contains 92 g of Na+ ions per kg of water, calculate the molality of Na+ ions in the lake.