50.g of NaNO3 was dissolved in 1250 mL of water. what is the molality of the solution? [ Molar mass of NaNO3 = 85 g/mol

Approximately (note that .)

Explanation:

The molarity of a solution gives the number of moles of solute in each unit volume of the solution. In this solution in water,

Let be the number of moles of the solute in the whole solution. Let represent the volume of that solution. The formula for the molarity of that solution is:

.

In this question, the volume of the solution is known to be . That's in standard units. What needs to be found is , the number of moles of in that solution.

The molar mass (formula mass) of a compound gives the mass of each mole of units of this compound. For example, the molar mass of is means that the mass of one mole of

.

For this question,

.

Calculate the molarity of this solution:

.

Note that (one mole per liter solution) is the same as .