Experiment Presentation

  1. Determine density of vinegar sample.
    As a group, determine the density of a known liquid to validate your experimental technique. Then determine the density of vinegar with sufficient accuracy and precision. Each student should complete at least one trial.
    a. Step 1 Measure the mass of the container, measure the volume of the liquid measure the combined mass of the liquid and container.
    b. Step 2, determine the mass of the liquid alone and divide the mass by the volume.
  2. Standardization of sodium hydroxide solution with solid potassium acid phthalate. Design the titration to use about 15 mL of 0.25 M sodium hydroxide solution. The burette – which you will use to deliver the sodium hydroxide solution – has a capacity of 50 mL. Run a single trial as a group and then each student should complete at least three trials.
    a. Step 1 Weigh 0.8 g of dried KHP (MW = 204.23 g/mol) into an Erlenmeyer flask and dissolve in 50-75 mL of distilled water.
    b. Step 2, Record the amount of KHP and water used. Add 4 drops of indicator into the flask and titrate to the first permanent appearance of pink.
  3. Titration of vinegar sample
    Start with 10 mL of your vinegar sample and titrate with your standardized sodium hydroxide solution. List the steps needed for the titration. Each student should complete at least three trials.
    a. Step 1 Begin the titration by slowly adding NaOH (aq) from the burette to the vinegar in the Erlenmeyer flask. Swirl Erlenmeyer flask as you add the base to efficiently mix the chemicals.
    b. Step 2, Some pinkness may appear briefly in the flask as the base is added, but it will quickly disappear as the flask is swirled.
  4. Waste Disposal.
    Combine all your waste and neutralize using vinegar and sodium bicarbonate as needed. List the steps.
    a. Step 1 Prevention.
    b. Step 2 Preparation for reuse. Recycling.

Sample Solution