Osmolality, also called ionic molality, represents the number of dissolved particles in a solution. And we're going to say that when it comes to covalent compounds, the number of ions they have is just 1. Here, they don't break up into multiple particles or ions. We just keep them together as one molecule, so for them, it equals 1. Now the osmolality formula is that osmolality equals the number of ions times the molality of our solution or compound.

The way we approach this is we break up ionic compounds into ions, and we count the total number of ions and multiply by the molality of the solution. So if we take a look here, we have 2.5 mol of sodium chloride. Sodium chloride is an ionic compound that breaks up into 2 ions, sodium ion and chloride ions. That's a total number of 2 ions, so we're going to say here that the osmolality equals 2, because there are 2 ions, times the molality of our solution. So again, it's 2.5 mol of sodium chloride solution.

That would mean that our total ionic molality here would be 5 moles. So that's the approach you need to take when it comes to ionic molality, otherwise known as osmolality.