Kamran Abbasbeyli
Chemistry
Titration Lab Report
Introduction:
In order to find the concentration of acid in different types of Pepsi an experiment should be held. For such purpose the titration is the best way to find the concentration of acid in a liquid. Titration is an experiment when in the substance that is being tested either acid or base is being pored to neutralize it. If the concentration of a liquid that contains acid is being tested, then a base is added into the liquid. However, if the tested liquid contains base then acid is added to neutralize the solution. This change cannot be seen with a bare eye therefore before adding base or an acid the indicator is added to the solution. Indicator changes the color of the solution when the acid or base is neutralized in the substance.
Materials:
– Pepsi 500 ml
– Pepsi Max 500 ml
– Pepsi Diet 500 ml
– Burette stand
– Graduated cylinder (100 ml)
– Small graduated cylinder (10ml)
– Deionized water
– Sodium Hydroxide (NaOH)
– Large Beaker
– Small Beaker
– Methyl orange indicator
– Erlenmeyer flask
Purpose:
The purpose of this lab is to find out the different concentrations of acid in different types of Pepsi Cola
Hypothesis:
If you test the concentration of acid in different types of Pepsi cola, then Pepsi max will have the highest concentration of acid, because it has the strongest flavor and so will have the strongest acidity.
Methods:
Independent Variable: The type of Pepsi
By only changing the type of Pepsi, each soda is very closely related, yet still different enough to have a variation in pH
Dependent Variable: The concentration of acid in each type of Pepsi
This will be measured through a titration using NaOH as a base to react with diluted Pepsi, an acid
Controlled Variables: The controlled variables are, temperature, sugar level and water level. They all must be controlled otherwise we will not understand what in particular affects the pH of the drink and what will cause the outcome of the lab.
The controlled variables are maintaining the temperature, so as not to affect the reaction or volumes and concentrations of each reactant, as well as sugar level and water level for each trial, to avoid inaccurate results and inconsistencies in each trial.
Procedure:
1. Take a clean 10 mL graduated cylinder and drop 1mL of NaOH at the bottom
2. Рour this sodium hydroxide into the mixing beaker
3. Take a clean 100 mL graduated cylinder and pour 99 mL of deionized water into it
4. Рour this water into the mixing beaker and mix the substance to form the base
5. Рour the base solution into the burette and mark its location
6. Рour 20 mL of Pepsi Max into the 100 mL graduated cylinder, and pour into the mixing beaker
7. Pour 80 mL of deionized water into the 100 mL graduated cylinder, and pour into the mixing beaker
8. Take the Pepsi Max solution and measure out 20 mL into the graduated cylinder, and роur that amount into the Erlenmeyer Flask
9. Add 8-10 drops of the methyl orange indicator to the flask, and swirl so that it is mixed in the flask
10. Begin to slowly pour the base solution out of the burette into the waste beaker in order to get the air bubbles out
11. Мark how much of the base solution is left
12. Begin a slow pour or dropping of the base solution into the Erlenmeyer Flask
13. Periodically swirl the flask in order to ensure that the base is spreading out around the Pepsi Max solution, this will produce pink color that slowly spreads
14. Wait until the pink spreads from small drops in the Pepsi Max solution to flooding the solution with color, and stop the flow of the base solution
15. Record how much base solution is left
16. Clean out the the flask and waste beaker, and refill the burette with base solution as needed (steps 1 and 2)
17. Repeat steps 7-17 for two more trials, resulting in three for the Pepsi Max
18. Repeat steps 7-18 for the other two variables of Pepsi (the Pepsi and Pepsi Diet)
Data Collection:
Volume of NaOH in (L)
Trial 1
Trial 2
Trial 3
Pepsi
0.012
0.023
0.018
Pepsi Max
0.01195
0.0111
0.0167
Pepsi Diet
0.0239
0.02525
0.0124
This chart clearly shows difference between the Pepsi solutions. The amount of NaOH needed to neutralize the acid in each sample varies. As can be seen from the chart it took a lot less base to neutralize the acid in the Pepsi Max solution. Also from the table it cam be seem that for Pepsi Diet it almost twice as much base to neutralize the acid. In order to find the concentration of acid in each Pepsi an equation must be solved.
Base volume x Base concentration = Base moles
Moles of base = Moles of acid
Moles of acid / Volume of acid= Concentration of acid
By completing this equation, the concentration of acid in the solution can be found.
Concentration of Acid in each solution of Pepsi
Trial 1
Trial 2
Trail 3
Average
Uncertainty
Pepsi
0.024
0.046
0.0374
0.0358
0.007333333
Pepsi Max
0.0239
0.0222
0.0334
0.0265
0.003733333
Pepsi Diet
0.0478
0.0505
0.0248
0.041033333
0.008566667
This chart backup my hypothesis that If you test the concentration of acid in different types of Pepsi cola, then Pepsi max will have the highest concentration of acid, because it has the strongest flavor and so will have the strongest acidity.
Data Analysis:
The graph above shows how significantly the level of acidity of Pepsi Max differs from Pepsi and Pepsi Diet. The table shows that the Peps Max has a lower concentration of hydronium which means that it is also the most acidic Pepsi. The reason behind that might be that the Pepsi company uses different ways of preparing different Pepsi drinks. Pepsi Max is considered to be Pepsi with the most flavor. The level of acidity might be cause by the chemicals that are added into the drink to make it taste stronger. Pepsi Diet is least flavored and least sweet drink and that is why it has such a low concentration of acid.
Conclusion:
With all the data looked ant and analyzed it is clear that more flavor a Pepsi contains more acidic it is. This supports my hypothesis that Pepsi Max with most flavor will be the most acidic Pepsi. The reason why the concentration of acid differs so much between the three sample of Pepsi is not very clear since the process of making the soda drink is not fully known.
Evaluation:
Data is pretty reliable as the numbers make sense. Since there weren’t a lot of trials some inaccuracy might occur in the data. From the graph error bars can be seen. Relatively to the graph they are small so is the chance of an error. Even though error bars are small some random errors might have occurred during the experiment. Pouring not right amount of base during the lab is one of many errors that could have happened. When making the base for the burette some of the liquid stays in the cylinder slightly changing the concentration of the solution. Same problem could have occurred with water since not all the drops of water come out of the cylinder and a slightly less precise data is written down. The experiment was reliable through the lab however some simple mistakes like not swirling or swirling weak might have give a different result. If the solution is not swirled, it is very easy to make a mistake since the whole solution might turn pink however if you swirl it will go to orange or even back to original. There is no way of making sure the lab is 100% accurate but it is precise even though it could have some minor errors.