How many moles of H. could be neutralized with this of hydroxide amount OST LAB
ID: 505292 • Letter: H
Question
How many moles of H. could be neutralized with this of hydroxide amount OST LAB QUESTIONS Discuss the main sources of error in this experiment. experimental Sally Chemist is attempting to determine the mass of acetic acid in vinegar using the procedure described above. Below is an excerpt from her lab book: a. Prepared vinegar analyte 25.0 mL vinegar Mass of vinegar 25.20 g Added 75.0 mL H Added 2 drops phenolphthalein Temperature: 27.0 C Manufacturer's mass acetic acid 3.5% b. Prepared burette Cleaned and dried burette Filled with standardized NaOH solution 0.201 M c. Titration Initial burette reading: 5.12 mL Final burette reading: 78.67 ml. Solution is light pink Room temp changed. i. What is the density of her vinegar sample? ii. se the manufacturers reported mass acetic acid to estimate how many moles of acetic acid are present in her analyte. iii. Use your result from ii to estimate how many ml of standardized Na solution she will need to reach the equivalence point. iv Use Sally's data to calculate the molarity of acetic acid in her vinegar sample. Use the results from iv to calculate the mass of acetic acid in Sally's vinegar sample. vi. How would the following experimental errors affect Sally's experimental result?Explanation / Answer
A)
If burette is not dry while adding std.NaOH, it's molarity slightly decreases and hence equivalence point increases slightly,hence calculated molarity of acetic acid also increases.
equation use to calculate unknown molarity is
M1V1=M2V2
B)
Since the bubble is there during entire experiment it will not effect the value.
C)
Since the bubble dislodged during the experiment, equivalence point increases and hence molarity of acetic acid also increases.
D)
If 95 ml water is added equivalence point decreases and hence molarity also decreases. But density remains constant.
E)
Since equivalence point overshot, hence molarity of acetic acid increases.