An aqueous KNO3 solution is made using 73.4g of KNO3 diluted to a total solution volume of 1.86 L. Calculate the molarity of the solution. (Assume a density of 1.05 g/ml for the solution.)
You do not need the density to solve since the total volume is given
Molarity=moles/liters
73.4g of KNO3/101.1032 g of KNO3/mol= moles of KNO3
Molarity=moles/liters=moles of KNO3/1.86L
To calculate the molarity of the KNO3 solution, we need to first determine the number of moles of KNO3 present in the solution, and then divide that by the volume of the solution in liters.
Step 1: Calculate the number of moles of KNO3.
Given the mass of KNO3 as 73.4 grams, we need to convert this mass to moles using the molar mass of KNO3. The molar mass of KNO3 can be calculated by adding up the atomic masses of potassium (K), nitrogen (N), and oxygen (O).
Molar mass of KNO3 = (atomic mass of K) + (atomic mass of N) + (3 * atomic mass of O)
= (39.1 g/mol) + (14.0 g/mol) + (3 * 16.0 g/mol)
= 39.1 g/mol + 14.0 g/mol + 48.0 g/mol
= 101.1 g/mol
To calculate the number of moles of KNO3, divide the mass by the molar mass:
Number of moles = mass / molar mass
= 73.4 g / 101.1 g/mol
≈ 0.7254 mol
Step 2: Calculate the molarity of the solution.
The molarity (M) of a solution is defined as the number of moles of solute divided by the volume of the solution in liters.
Molarity = number of moles / volume of solution
Given that the total solution volume is 1.86 L, we can substitute the values into the formula:
Molarity = 0.7254 mol / 1.86 L
≈ 0.390 M
Therefore, the molarity of the aqueous KNO3 solution is approximately 0.390 M.