Put name here
Put Title Here
Problem: Write questions from the top of page 107 of the Lab Manual.
Background Information:
Answer these questions in complete sentences. If you need, refer to page 107 of the Lab Manual.
What is the acid-base reaction of the lab?
What is titration? What is it used for?
How do you know when the acetic acid is neutralized?
Hypothesis:
If we use titration to determine the amount of acetic acid in vinegar, then we can determine how accurate the
advertised amount is.
Experiment:
Safety:
This lab requires you to wear goggles and gloves.
Materials:
List the materials here (except the 50mL graduated cylinder and dropper bottle, instead list “buret of 1.0M
NaOH”)
Procedure:
Part 1
1. Put about 10mL of distilled water into the buret.
2. Count how many drops of water are released in 1mL. Record in Table 1.
3. Repeat step two twice.
4. Average these trials to find your buret’s drops per milliliter.
5. Drain all of the distilled water out of the buret. Close the stopper and pour in about 20mL of 1.0NaOH to
prepare for the next portion of the lab.
Part 2
1.
2.
3.
4.
5.
6.
Weigh a clean dry 125mL Erlenmeyer flask. Record in Table 2.
Measure about 1.6mL of vinegar in the 10mL graduated cylinder, and add it to the Erlenmeyer flask.
Weigh the flask and the vinegar. Record in Table 2.
Add approximately 25mL of distilled water to the flask. Swirl to mix.
Add 3-4 drops of phenolphthalein indicator to the vinegar. Swirl to mix.
Add drops of NaOH slowly to your Erlenmeyer flask, while counting the drops. Swirl to mix after every
few drops.
7. When a light pink color persists for 30-60 seconds, turn off the buret stopper. Record the total number of
drops in Table 2.
8. Repeat steps 1-7 another two times.
9. Rinse the titration down the sink with water. Rinse the glassware with tap, then distilled water.
Data/Observations:
Table 1. Calibrating the buret
Trial
Drops in 1mL
1
Qualitative Observations:
2
3
average
Table 2. Raw Data
Trial Mass of empty flask (g)
1
Mass of flask and vinegar (g)
Volume of NaOH (drops)
2
3
Calculations:
Table 3. Sodium Hydroxide Volume and Moles
Trial Volume NaOH (mL)
Volume NaOH (L)
1
Moles NaOH (mol)
2
3
Table 4. Acetic Acid Moles and Mass
Trial Mass Vinegar (g)
Moles CH3COOH (mol)
1
Mass CH3COOH (g)
Percent Mass (%)
2
3
Show one trial’s calculation of how you converted moles CH3COOH to grams CH3COOH. You don’t
have to show how you got the molar mass, but you do need to show that you used it.
PercentMass =
MassCH 3COOH(g)
´100
MassVinegar(g)
Show one trial’s percent mass calculation here
Table 5. Percent Error
Average Percent Mass CH3COOH
PercentError =
Avg%Mass - 5.00%
´100
5.00%
Percent Error
Show the percent error calculation here
Draw Conclusions
In this space, write the answers to these questions. Full points will be given for complete sentences.
-Was your hypothesis correct? Why or why not? (NOTE: You should definitely refer to your percent error
here as an argument to either support or refute your hypothesis.)
-What are at least two sources of experimental error that may have affected your results?
-When the “end-point” of your titration is reached, what is true about the moles of acid and moles of base?