Question

A student wants to make 50-mL of a 0.6 mg/L solution of acetic acid. She will be making the solution by diluting a stock with a concentration of 2.0 mg/L. Put the steps for her dilution in order. 4. Cap the flask and invert several times to mix. 2. Fill the volumetric flask with deionized water until the meniscus touches the mark. 6. Swirl the flask to mix the contents. 1. Obtain a 50-mL volumetric flask. 3. Use a pipet to add the appropriate volume of stock solution to the flask. 2. Add approximately 10 mL of deionized water to the empty flask.

Answer 1

Answer:

The steps in order are;

1. Obtain a 50-mL volumetric flask

2. Add approximately 10 mL of deionized water to the empty flask

3. Use a pipet to add the appropriate volume of stock solution to the flask

4. Cap the flask and invert several times to mix

5. Fill the volumetric flask with deionized water until the meniscus touches the mark

6. Swirl the flask to mix the contents

The volume of the acetic acid to be added to the solution is 15 mL

Explanation:

The given steps are;

4. Cap the flask and invert several times to mix

5. Fill the volumetric flask with deionized water until the meniscus touches the mark

6. Swirl the flask to mix the contents

1. Obtain a 50-mL volumetric flask

3. Use a pipet to add the appropriate volume of stock solution to the flask

2. Add approximately 10 mL of deionized water to the empty flask

The given parameters are;

The volume of the volumetric flask = 50-mL

The concentration of the final solution of acetic acid = 0.6 mg/L

The concentration of the stock solution = 2.0 mg/L

Let 'x' represent the volume of the stock solution added, we have;

2.0 mg/L·x + (50 - x)×0 = 0.6 mg/L × 50-mL

x = 0.6 mg/L × 50-mL/(2.0 mg/L) = 15 mL

The volume of the stock solution to be added, x = 15 mL