How many grams of KNO3 (molar mass = 101.103 g/mol) should be used to make 325.0 ml of 0.070 M solution?
How many moles do you need?
mols = M x L = ?
Then mols = grams/molar mass. You know molar mass and mols, solve for grams.
To calculate the number of grams of KNO3 needed to make a given solution, we can use the formula:
Mass (in grams) = Molarity (in moles/L) x Volume (in L) x Molar Mass (in g/mol)
First, we need to convert the given volume from milliliters to liters:
325.0 ml = 325.0 ml ÷ 1000 ml/L = 0.325 L.
Next, we can substitute the given values into the formula:
Mass = 0.070 moles/L x 0.325 L x 101.103 g/mol.
By multiplying these values together, we can find the number of grams of KNO3 needed:
Mass = 0.022678 moles x 101.103 g/mol.
Finally, we calculate the mass:
Mass ≈ 2.294 g.
Therefore, approximately 2.294 grams of KNO3 should be used to make 325.0 ml of 0.070 M solution.