Molality id defined as (moles of a solute)/(kg of solvent). So the concentration of Ca in the river water would be (13.4 mg/kg) * (1/1000 g/mg) * (1/40.078 mol/g) = 3.34 x 10^-4 mol/kg
The key to solving any concentration problem is knowing what units you're starting with and what units you want to end with. I'll leave the Na for you to solve, but the solution is essentially the same. Try to make sure your units cancel out to the proper unit at the end.
The concentrations of Ca and Na in a sample of river water are 13.4 mg/kg and 5.2 mg/kg. Express the concentration in molality
1 answer
1 answer