What mass of K2SO4 would you measure out to prepare 550mL of a .76 M solution?
How many moles do you need. M x L = moles.
moles = grams/molar mass. Solve for grams.
To calculate the mass of K2SO4 required to prepare a 550 mL solution with a concentration of 0.76 M, you need to follow these steps:
Step 1: Start with the given information.
- Volume of the solution (V) = 550 mL = 0.55 L
- Concentration of the solution (C) = 0.76 M
Step 2: Use the formula for molarity (M) to calculate the number of moles (n) of solute.
- Molarity (M) = moles of solute (n) / volume of solution (V)
Rearrange the formula to solve for moles of solute:
- n = M × V
Substitute the given values:
- n = 0.76 mol/L × 0.55 L
- n = 0.418 mol
Step 3: Use the molar mass (Molar Mass of K2SO4) to convert moles of solute to grams of solute.
- The molar mass of K2SO4 is calculated as follows:
- 2 (molar mass of K) + 1 (molar mass of S) + 4 (molar mass of O)
- 2 (39.10 g/mol) + 1 (32.06 g/mol) + 4 (16.00 g/mol)
- 78.20 g/mol + 32.06 g/mol + 64.00 g/mol
- 174.26 g/mol
Finally, calculate the mass of K2SO4:
- Mass = moles of solute × molar mass
- Mass = 0.418 mol × 174.26 g/mol
Using a calculator:
- Mass ≈ 72.68 g
Therefore, you would measure out approximately 72.68 grams of K2SO4 to prepare a 550 mL solution with a concentration of 0.76 M.