Calculate the molarity of a solution prepared by dissolving 89 g of KNO₃ in 0.525 L of water. Show your work.
well, how many grams of KNO3 in a whole liter?
89 / 0.525 = ?
then how many mols is that ?
well 1 mol = 39 + 14 + 3*16 = 101 grams / 1 mol
so
? grams * 1 mol/101 grams
To calculate the molarity of a solution, you need to know the number of moles of the solute (KNO₃) and the volume of the solution.
1. Convert the given mass of KNO₃ from grams to moles.
- To do this, divide the mass by the molar mass of KNO₃. The molar mass of KNO₃ is calculated by adding up the atomic masses of its elements. The atomic masses are: potassium (K) = 39.10 g/mol, nitrogen (N) = 14.01 g/mol, and oxygen (O) = 16.00 g/mol.
- Molar mass of KNO₃ = (39.10 g/mol) + (14.01 g/mol) + (3 * 16.00 g/mol) = 101.11 g/mol
- Moles of KNO₃ = 89 g / 101.11 g/mol
2. Convert the given volume of water from liters to moles.
- Since water does not change its molar concentration, its molar volume is 1 L/mol.
- Moles of water = 0.525 L * (1 mol/1 L)
3. Calculate the molarity of the solution.
- Molarity (M) is defined as moles of solute divided by the volume of the solution in liters.
- Molarity = Moles of KNO₃ / Volume of solution in liters
Now let's plug in the values and calculate:
Moles of KNO₃ = 89 g / 101.11 g/mol = 0.880 mol
Moles of water = 0.525 L * (1 mol/1 L) = 0.525 mol
Molarity = 0.880 mol / (0.525 L + 1 L) = 0.880 mol / 1.525 L = 0.576 M
Therefore, the molarity of the solution prepared by dissolving 89 g of KNO₃ in 0.525 L of water is 0.576 M.
0.525 L of water, so assume this is the volume of the solution
Molarity= (89/formulamassKNO3) /.525 L solution
so figure the formula mass of potassium nitrate.