How many grams of potassium nitrate, KNO3 are required to make 250 mL solution with a molarity of 0.40 M?
How many mols do you want? That's M x L = mols.
Then mols = g/molar mass. You know mols and molar mass, solve for grams.
To calculate the number of grams of potassium nitrate (KNO3) required to make a 250 mL solution with a molarity of 0.40 M, you can use the formula:
Molarity (M) = moles of solute / liters of solution
First, we need to calculate the number of moles of KNO3 required:
Moles of solute = Molarity × liters of solution
Since the volume is given in milliliters, we need to convert it into liters:
Liters of solution = 250 mL ÷ 1000 mL/L = 0.250 L
Now we can plug in the values and solve for moles of KNO3:
Moles of solute = 0.40 M × 0.250 L = 0.10 moles
Next, we need to convert moles of solute into grams. To do this, we need the molar mass of KNO3, which is:
Molar mass of KNO3 = (atomic mass of potassium) + (atomic mass of nitrogen) + (3 × atomic mass of oxygen)
Molar mass of KNO3 = (39.10 g/mol) + (14.01 g/mol) + (3 × 16.00 g/mol) = 101.10 g/mol
Finally, we can calculate the grams of KNO3 required:
Grams of solute = moles of solute × molar mass of KNO3
Grams of solute = 0.10 moles × 101.10 g/mol = 10.11 grams
Therefore, you would need approximately 10.11 grams of potassium nitrate (KNO3) to make a 250 mL solution with a molarity of 0.40 M.
To calculate the number of grams of potassium nitrate (KNO3) required to make a solution with a specific molarity, you need to know the molar mass of the compound and the volume of the solution.
Step 1: Calculate the number of moles of KNO3:
Molarity (M) = Moles (mol) / Volume (L)
Given:
Molarity (M) = 0.40 M
Volume (V) = 250 mL = 250/1000 L = 0.25 L (convert mL to L)
Rearranging the equation:
Moles (mol) = Molarity (M) * Volume (L)
Moles (mol) = 0.40 M * 0.25 L
Moles (mol) = 0.10 mol
Step 2: Calculate the mass of KNO3:
Moles (mol) = Mass (g) / Molar Mass (g/mol)
Given:
Moles (mol) = 0.10 mol
Molar Mass of KNO3 = 101.10 g/mol (potassium = 39.10 g/mol, nitrogen = 14.01 g/mol, oxygen = 16.00 g/mol)
Rearranging the equation:
Mass (g) = Moles (mol) * Molar Mass (g/mol)
Mass (g) = 0.10 mol * 101.10 g/mol
Mass (g) = 10.11 g
Therefore, to make a 250 mL solution with a molarity of 0.40 M, you would need 10.11 grams of potassium nitrate (KNO3).