posted by casey on .
An aqueous solution is 22.0% by mass silver nitrate, AgNO3, and has a density of 1.22 g/mL. what is the molality of silver nitrate in the solution?
22.0% AgNO3 by mass means 22.0 grams AgNO3 per 100 g solution. That is equivalent to 220 g/1000g solution.
The 1000 g solution is made of 220 g AgNO3 + 780 g water.
How many moles AgNO3 in 220 g AgNO3. That will be 220/molar mass AgNO3 (approximately 1.3 moles.
molality = moles/kg solvent.
m = 1.3 moles/0.780 kg solvent = about 1.7 m.
Check my work.