how to prepare a 250 mL solution of .15 M K2SO4 with a volumetric flask
You need how many mols? That's M x L = ?mols K2SO4.
mols = grams/molar mass. You know molar mass and mols, solve for grams.
Here is how you do it. Weigh ? grams K2SO4, place in a 250 mL volumetric flask, add SOME water and swirl until K2SO4 is completely dissolved, then add water to the mark on the volumetric flask. Mix thoroughly.
To prepare a 250 mL solution of 0.15 M K2SO4 using a volumetric flask, you will need to follow these steps:
Step 1: Determine the amount of solute needed
The concentration of the solution is given as 0.15 M, which means there are 0.15 moles of K2SO4 in 1 liter (1000 mL) of solution. So, for a 250 mL solution, we need 0.15 moles/L * 0.250 L = 0.0375 moles of K2SO4.
Step 2: Calculate the mass of K2SO4 needed
To calculate the mass of K2SO4 needed, you will need to know the molar mass of K2SO4. The molar mass can be calculated by adding the atomic masses of each atom in the compound. For K2SO4, the molar mass is 174.2592 g/mol.
Mass of K2SO4 = moles of K2SO4 * molar mass
Mass of K2SO4 = 0.0375 moles * 174.2592 g/mol = 6.54 grams.
Step 3: Measure the appropriate amount of K2SO4
Using a balance, measure out 6.54 grams of K2SO4 using an analytical balance, making sure to add or subtract small amounts as needed to obtain the exact mass.
Step 4: Transfer the solute to the volumetric flask
Using a funnel, transfer the measured amount of K2SO4 into the volumetric flask.
Step 5: Add some distilled water
To dissolve the K2SO4, add a small amount of distilled water into the volumetric flask. Swirl gently to dissolve the solute completely.
Step 6: Add more distilled water
After the solute is completely dissolved, fill the volumetric flask up to the 250 mL mark with distilled water. Be careful not to go over the mark.
Step 7: Mix the solution
Gently mix the solution by inverting the volumetric flask several times. This will ensure that the solution is thoroughly mixed.
Congratulations! You have prepared a 250 mL solution of 0.15 M K2SO4 using a volumetric flask.
To prepare a 250 mL solution of 0.15 M K2SO4 using a volumetric flask, you will need to follow these steps:
1. Obtain the necessary materials: You will need a volumetric flask with a 250 mL capacity, K2SO4 (potassium sulfate) powder, a balance or analytical scale, and distilled water.
2. Calculate the amount of K2SO4 needed: Use the formula for molarity, which is Molarity (M) = moles of solute / volume of solution (in liters). You are given the desired molarity (0.15 M) and volume (250 mL = 0.250 L), so rearrange the formula to solve for moles of solute:
Moles of solute = Molarity × Volume of solution
Moles of K2SO4 = 0.15 M × 0.250 L
3. Calculate the mass of K2SO4: Use the molar mass of K2SO4 to convert moles into grams. The molar mass of K2SO4 is:
K: 39.10 grams/mol × 2 = 78.20 g/mol
S: 32.07 g/mol
O: 16.00 g/mol × 4 = 64.00 g/mol
Total molar mass: 78.20 g/mol + 32.07 g/mol + 64.00 g/mol = 174.27 g/mol
Mass of K2SO4 = Moles of K2SO4 × Molar mass of K2SO4
4. Weigh the K2SO4: Using a balance or analytical scale, carefully measure and weigh the calculated mass of K2SO4.
5. Transfer the weighed K2SO4 into the volumetric flask: Use a funnel or other suitable method to transfer the weighed K2SO4 powder into the volumetric flask. Be careful to avoid spillage.
6. Add distilled water to the flask: Fill the volumetric flask with distilled water slowly and carefully, leaving some space at the top to allow for mixing.
7. Mix and dissolve: Gently swirl or use a stirring rod to mix the contents of the flask until the K2SO4 is completely dissolved in the water.
8. Adjust the volume: If needed, adjust the volume of the solution to exactly 250 mL by carefully adding or removing small amounts of distilled water using a dropper or pipette.
9. Seal the flask: Once the desired volume is reached, ensure the flask's stopper or cap is tightly sealed to prevent any leakage.
Congratulations! You have successfully prepared a 250 mL solution of 0.15 M K2SO4 using a volumetric flask. Remember to label the flask appropriately for future use.