Question

Say you have a 5.0 M stock solution of ‘stuff’. How much of that stock is needed to make 150 mL of a 0.65 M dilution of that solution? How much dH2O is needed to complete the dilution?

Answer 1

To prepare a 0.65 M dilution of a 5.0 M stock solution, you will need approximately 19.5 mL of the stock solution and about 130.5 mL of water.

Step-by-step explanation:

To prepare a 0.65 M dilution of a 5.0 M stock solution, you will need to calculate the volume of the stock solution required and the amount of water needed to complete the dilution.

Calculating the volume of stock solution:

Using the formula (stock concentration)(stock volume) = (diluted concentration)(diluted volume), we can rearrange the formula to solve for the stock volume:

(5.0 M)(stock volume) = (0.65 M)(150 mL)

Stock volume = (0.65 M)(150 mL) / 5.0 M ≈ 19.5 mL

Calculating the amount of water:

The amount of water needed to complete the dilution is equal to the final diluted volume minus the volume of stock solution used.

Water needed = 150 mL - 19.5 mL ≈ 130.5 mL