Question

How would you prepare 0.30 L of an 8.2% ammonium sulfate solution?

a. Dissolve 24.6 g of ammonium sulfate in water and adjust the volume to 0.30 L.
b. Dilute 8.2 L of ammonium sulfate to 0.30 L.
c. Mix 0.30 L of ammonium sulfate with 8.2 L of water.
d. Boil 0.30 L of water with 8.2 g of ammonium sulfate.

Answer 1

To prepare 0.30 L of an 8.2% ammonium sulfate solution, dissolve 24.6 g of ammonium sulfate in a small amount of water, transfer it to a volumetric flask, and then add water up to the 0.30 L mark.

Step-by-step explanation:

To prepare 0.30 L of an 8.2% ammonium sulfate solution, we first need to calculate the mass of ammonium sulfate required. This can be done using the formula: percentage concentration = (mass of solute / volume of solution) x 100%. So, the mass of the solute needed is 0.30 L x 8.2 / 100, which is equal to 24.6 grams. Then, following the steps for preparing solutions, the correct procedure would be to:

1. Dissolve 24.6 g of ammonium sulfate in a small amount of water to ensure it is fully dissolved.
2. Transfer this solution to a volumetric flask.
3. Add additional water to the volumetric flask until the bottom of the meniscus is at the 0.30 L mark of the flask.

This process ensures an accurate concentration as the hydrated ions take up space in the solution and this must be accommodated for to achieve the desired final volume.