Shurp!

I. Purpose:
In this experiment we experimented with titration. We saw the effects of titration on an acid and then on a base. The acid we used was hydro chloric acid and the base was ammonia. The acid turned pinkish red when properly titrated and the base turned clear. We used phenolphthalein as the titrate which turns red in acidic solutions and clear in basic solutions. The control aspects of this lab were the hydrochloric acid and ammonia. The independent variable was the titrate the phenolphthalein. We measured how many drops of the phenolphthalein it took to titrate the acid or the base.

Research question:
Is it possible to accurately observe the effects of titration on an acid and a base?
Hypothesis:
1.If we add 18 mL of titrant to the flask containing the vinegar and indicator (phenolphthalein), then the endpoint of titration will be reached, causing the solution to turn pink. 2. If we add 14 mL of titrant to the flask containing HCI and the indicator (phenolphthalein), then the endpoint of titration will be reached, causing the solution to turn colorless.
II. Data
Table 1: Acid or Base in household cleaner
Name of cleaner or vinegar
Vinegar
Acid or Base Contained
NaOH
Molecular Mass
60.6 g

Table 2: Known (acid or base) in Unknown (vinegar or cleaner)

Trial 1
Trial 2
1. Mass of flask + unknown

148.5 g
147.9 g
2. Mass of empty flask

127.7 g
127.7 g
3. Mass of unknown

20.8 g
20.2 g
4. Cm3 known to titrate unknown

18.5
17.9
5. Liters of Known

0.02
0.02
6. Moles of known acid

0.333 M
0.333 M
7. Moles of acid or base in unknown

0.520 M
0.520 M
8. Mass of acid or base in unknown

18.9 g
18.9 g
9. Percent acid or base in unknown

3.84 %
3.84 %
10. Manufacture’s claim

5.8 %
5.9 %
11. Percent deviation

23 %
23 %

Table 3

Trial 1
Trial 2
1. Liters of Unknown, NaOH
0.020 L
0.020 L
2. Molarity of HCl
1.0 M
1.0 M
3. Liters of HCl used to titrate
0.0141 L
0.0154 L
4. Calculated Molarity of unknown NaOH
0.50M
0.50M
5. Actual Molarity of unknown NaOH
0.70M
0.70M
6. Difference
0.20M
0.20M
7. Percent Error
28.5%
28.5%

Questions
1. 5.14g of a household cleaner containing HCl requires 18.5cm3 of 1.0M NaOH solution to neutralize. What is the percent of HCl in the cleaner? Be sure to write out the balanced equation for this reaction.
The balanced equation of the reaction is HCl + NaOH –> NaCl + H2O. The moles of NaOH = moles of HCl. The moles of NaOH is 1 x 0.0185 L which equals 0.0185 moles MM(HCl). This means that 36.5 g/mol g(HCl) = 0.0185 x 36.5 which becomes 0.675 g of HCl. The % HCl is (0.675/5.14) x 100 % HCl which becomes 0.131 x 100 = 13.1 %. Therefore there is 13.1 %of HCl in the cleaner
2. One of the reasons that acids are used in household cleaners is to dissolve "rust" stains from hard water containing iron. These stains may contain Fe(OH)3. Write a balanced equation for the reaction of HCl with Fe(OH)3.
The balanced equation is 3HCl + Fe(OH)3 -> FeCl3 + 3H2O
III. Conclusion The purpose of this experiment was to find the effects of titration on an acid and on a base. The specific acid we used during this experiment was hydrochloric acid and the base we used was ammonia. The observable effects of acid is that the color turned pinkish red when properly titrated while the base turned colorless. In order to change the color, we used phenolphthalein as the titrate which turns acidic solutions into a red color and the basic solutions into a clear color. The control aspects we used in this lab were the hydrochloric acid and ammonia. The independent variable was the titrate, phenolphthalein. Our group measured how many drops of the phenolphthalein it took to titrate the acid or base. Yes, the purpose was accomplished based on how we were able to observe the effects of titration on an acid and a base. By adding the titrate, phenolphthalein, we were able to record how many mL it took for the endpoint of titration to be reached in both acid and base. Also, our group accurately observed how many drops of the phenolphthalein it took to titrate the acid or base. Also, our groups hypothesis was also proven based on our tables. By adding 18 mL of titrate to the flask containing vinegar and indicator phenolphthalein, it caused the solution to turn pinkish red, thereofre, the endpoint of titration has been reached. Also, by adding 14 mL of titrant to the flask containing HCI and the indicator phenolphthalein, it caused the solution to turn colorless, therefore, the endpoint of titration has been reached. The errors that our group had committed while conducting this lab was that we accidentally added to much of the indicator phenolphthalein, which as a result, turn the acidic solution into a red color instead of pink. This error would also cause our group having inaccurate data. Another error that we made was that our group accidentally did not add the indicator phenolphthalein before adding the acid or base. This will lead to an inaccurate graph as well since we need to measure how many mL it takes for the endpoint of titration to be reached. Specific suggestions to improve the materials would to include a more simple equipment to measure how many mL it took for the titration to reach its an endpoint. This will significantly boost the accuracy of the groups data since its easier to measure how many mL has been already used and prevent an error due to losing track of how many mL our group had already used. Therefore, adding a more simple equipment to help us keep track of how many mL had been already used, will result in accurate data.