Sorry for the weird picture, I started the problem but got confused and scribbled it all out so I had to crop it out. A detailed explanation would be so helpful thank you!!
15. Calculate the mass--volume percent concentration for a 3.25 M NaOH solution. . Show math expressions with substitutions.
3,) Based on your coarse titration volume, do you expect the acetic acid solution to have a higher or lower concentration than the NaOH solution?
higher could you please tell me if number 3 is right
please help with these 2 questions
Part 1: Prepare the NaOH Solution
Lab Results
How many mL of water were used to prepare the NaOH solution?
200mL
Data Analysis
Calculate the molarity of the NaOH solution. The molar mass of NaOH is 39.997 g/mol.
0.1M
Calculate the amount of benzoic acid to be neutralized by 20.00 mL NaOH solution, in both moles and grams. The molar mass of benzoic acid is 122.12 g/mol.
1.207 g
Part 2: Perform a Coarse Titration
Lab Results
Record the following data from your course titration in the table below.
mass of benzoic acid used (g)
0.26614g
pH of benzoic acid solution before titration
2.96
volume of NaOH in the burette before titration (mL)
50.0mL
volume of NaOH in the burette after titration (mL)
28.89mL
volume of NaOH dispensed in the titration (mL)
21.11mL
Data Analysis
How do you expect your coarse titration volume to compare to your fine titration volumes?
I expect the values to be a little off from each other since in the first titration we let out a lot at a time and didnt slowly do the titration. should only be off by a few mL.
Part 3: Perform Fine Titrations
Lab Results
Record the volume of NaOH solution dispensed in the 3 fine titrations.
20 mL dispenced ,20.34mL, 20.30mL
Data Analysis
Calculate the average concentration of the NaOH solution, using the average volume of NaOH solution dispensed in the 3 fine titrations. Report your answer using enough significant figures to distinguish it from the expected concentration of 0.100 M.
V = (V1 + V2 + V3) / 3
V = (20.03 mL + 20.06 mL + 20.02 mL) / 3 = 20.04 mL
M = n / V = 0.00200 moles / 0.02004 L = 0.0998 M
Learning objective: Determine the concentration of a solution.
20.21= ----> 0.0999M
Experiment 2: Use the Standardized NaOH Solution to Determine the Concentration of an Acid
Part 1: Perform a Coarse Titration
Lab Results
What was the pH at the end point of the coarse titration?
3.87ph
Data Analysis
Based on your coarse titration volume, do you expect the acetic acid solution to have a higher or lower concentration than the NaOH solution?
higher
Part 2: Perform Fine Titrations
Lab Results
For the 3 fine titrations of the acid of unknown concentration, fill in the following data.
Titration #1
Titration #2
Titration #3
volume of acid (mL)
59.11
40.97
40.98
volume of NaOH dispensed (mL)
9.05
9.03
9.02
Data Analysis
Calculate the following quantities and record the data in the table below.
average volume of NaOH solution dispensed (mL)
9.03
average number of moles of NaOH dispensed
average concentration of the acid (mol/L)
Conclusions
Phenolphthalein is pink over the range of pH 8 â 12. Why was it a useful indicator of when the equivalence point was reached?
This was helpful because once I got to the ph of 7 I knew that I would be getting closer to the end point which would change the color to pink.
Suppose a student titrated a sample of monoprotic acid of unknown concentration using a previously standardized solution of NaOH.
volume of 0.125 M NaOH dispensed
24.68 mL
volume of acid solution
50.00 mL
Given the data in the figure above, what is the concentration of the unknown acid?
0.0617M
Lab NOTES:
ex1
Take sodium hydroxide from the Materials shelf and add 0.800 g to the beaker.
Take water from the Materials shelf and add 200 mL to the beaker.
