Hi, I need help with A and B please. I appreciate it and thank you ahead of time!
A.
Molarity of standard HCl solution = 0.1 M
Unknown - K
Standardization of NaOH solution
First Trial First Trial Second Trial Second Trial Buret Readings HCl NaOH HCl NaOH Final Volume, mL 25 25 25 25 Inital Volume, mL 45 45.1 50 50 Volume Used, mL 20 20.1 25 25
1. What is the Molarity of NaOH
2. What is the average Molarity?
B.
First Trial First Trial Second Trial Second Trial Buret Readings CH3COOH NaOH CH3COOH NaOH Final Volume, mL 50 37 51 43 Inital Volume, mL 20 50 20 55 Volume Used, mL 30 13 31 12
1. What is the percent of acetic acid of your unknown?
Hi, I need help with A and B please. I appreciate it and thank you ahead of time!
A.
Molarity of standard HCl solution = 0.1 M
Unknown - K
Standardization of NaOH solution
| First Trial | First Trial | Second Trial | Second Trial | |
| Buret Readings | HCl | NaOH | HCl | NaOH |
| Final Volume, mL | 25 | 25 | 25 | 25 |
| Inital Volume, mL | 45 | 45.1 | 50 | 50 |
| Volume Used, mL | 20 | 20.1 | 25 | 25 |
1. What is the Molarity of NaOH
2. What is the average Molarity?
B.
| First Trial | First Trial | Second Trial | Second Trial | |
| Buret Readings | CH3COOH | NaOH | CH3COOH | NaOH |
| Final Volume, mL | 50 | 37 | 51 | 43 |
| Inital Volume, mL | 20 | 50 | 20 | 55 |
| Volume Used, mL | 30 | 13 | 31 | 12 |
1. What is the percent of acetic acid of your unknown?
For unlimited access to Homework Help, a Homework+ subscription is required.
Related textbook solutions
Basic Chemistry
Principles of Chemistry Molecular Approach
Principles of Chemistry Molecular Approach
Chemistry: Structure and Properties
Chemistry: A Molecular Approach
Chemistry: A Molecular Approach
Principles of Chemistry: A Molecular Approach
Chemistry: The Central Science
Related questions
| 1.) average number of moles of NaOH dispensed |
|---|
| 2.)average concentration of the acid (mol/L) |
|---|
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 รขยย 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. Ph 2.96 inital volume in burett inital volume 50ml 1.) volume43.78mL volumes dispenced =6.22ml 2. volume =38.05 volume dispenced =11.95ml 3.)volume = 32.06 volume dispenced=17.94 4.28.89ml volume dispenced=21.11ml ph=10.95 -------------------------------------- Ex 2 inital ph= 2.96 volume30.33 dispence 20.05 1. volume 39.92ml volume dispenced=10.08 2.volume 29.66 voiume dispence 20.34 final ph10.43 initial valume in burett 50ml -------------------- ex3 final ph9.43 volume 30.28 volume dipenced=20.00 ---------------------------------------------------------------------- 2nd Ex initial ph 3.11 volume 50 1. volume 48.95mL dispenced 1.05mL ph 3.87 2. volume 45.88 dispenced 4.12 ph 4.67 3 volume 42.99 dispenced 7.01 ph 5.29 4 volume 39.93 dispence 10.07 ph 11.45 -------------------- F1 final ph 9.99 volume 59.11 dispenced 9.05 F2 ph 9.59 volume 40.97 dispenced 9.03 f3 ph 9.50 volume 40.98 9.02 |
1-How many grams of NaCl would be needed to prepare 150.00 L of a 1.402 M NaCl solution?
............................................................................................................................................................................
2- first a standardized solution of sodium hydroxide (NaOH) will be quantitatively diluted to about 0.1 M but not exactly 0.1M. The molarity of the dilute NaOH will be calculated! A similar quantitative dilution was done in experiment 3 when you diluted 5.0 M HCl to 0.50M HCl using a volumetric flask and pipet.
The second part of the experiment is very similar to the last part of experiment 6 where samples of the unknown were weighed out, dissolved in water, and titrated with the dilute NaOH using phenolphthalein as the indicator to determine the percent by mass of a compound in the unknown. The compound will be different than the compound used in experiment 6. The molecular formula of the compound will be provided during the final. You must know how to weigh by difference (Preweigh, tare sample and small container to zero, transfer sample to flask, and place the small container back on balance to get mass) and titrate the sample using the buret in order to do well.
Be sure to read the instructions for the practical toward the end the CHM151L lab manual and do the practice problem on the next page.
You will have 1.5 hours to do the practical. You may only use a calculator and a pencil on the practical. There is no talking during the practical such that students cannot help each other and the TA may only help you with equipment problems.
It would be a good idea to wash any glassware you might use the lab period before the lab practical. There will also be a help session before the lab practical.
At the end of the lab final you will wash all glassware used or any dirty glassware in your locker, wash your unknown vials and remove the labels, checkin your locker and return your key, and evaluate the lab.
Please put the following statements in the correct order relating to the day of the lab practical:
1 2 3 4 5 6 Wash all your glassware and unknown vials, checkin your locker, evaluate the lab, and check your grades.
1 2 3 4 5 6 Do at least 3 good trials (weigh and titrate sample) as time allows.
1 2 3 4 5 6 Start the lab practical by diluting the NaOH solution.
1 2 3 4 5 6 Before the day of the practical clean glassware, read the practical instructions and do the practice problem in the lab manual and complete the loncapa problems for the final.
1 2 3 4 5 6 Calculate the molarity of the dilute NaOH, the percent by mass of the compound in you unknown for each trial and then the median.
1 2 3 4 5 6 Come to the help session before the lab final.
............................................................................................................................................................................
3-
A NaOH solution was prepared by diluting 5.00 mL of 2.205 M NaOH to a final total volume of 100.00 mL. What is the exact molarity of the dilute NaOH (use 4-5 significant figures)?
............................................................................................................................................................................
4-For the problem above, select glassware and size from the list below to conduct the dilution.
| A | Amber Bottle |
| B | Mohr pipet |
| C | Buret |
| D | Volumetric Flask |
| E | Volumetric Pipet or Pipettor |
| F | Graduated cylinder |
| G | Erlenmeyer flask |
| H | Beaker |
A B C D E F G H <= Glassware used to transfer the 2.205 M NaOH to be diluted
A B C D E F G H <= Glassware used to measure the final volume of the diluted M NaOH.
5 10 15 20 25 50 100 250 500 1000 <= Volume of the glassware chosen to transfer the concentrated NaOH above
5 10 15 20 25 50 100 250 500 1000 <= Volume of the glassware chosen to contain the final dilute NaOH above.