Loading...

Messages

Proposals

Stuck in your homework and missing deadline? Get urgent help in $10/Page with 24 hours deadline

Get Urgent Writing Help In Your Essays, Assignments, Homeworks, Dissertation, Thesis Or Coursework & Achieve A+ Grades.

Privacy Guaranteed - 100% Plagiarism Free Writing - Free Turnitin Report - Professional And Experienced Writers - 24/7 Online Support

Least count of pipette in chemistry

22/10/2021 Client: muhammad11 Deadline: 2 Day

Lab 6: Determination of Ka for a Weak Acid

Procedure: To begin the experiment, carefully cut the tip of the phenolphthalein pipet and add exactly 2 drops of phenolphthalein solution to the unknown weak acid in the beaker. Then swirl the beaker to completely mix the unknown weak acid and phenolphthalein solution. Remove the cap of the Sodium Hydroxide and fill an empty pipet full of the solution. Add NaOH from the pipet into the beaker containing the 4 mL of unknown weak acid one drop at a time, swirling and observing the solution in the beaker after each drop until the color changes to a pale-pink color for at least 5 seconds. Count and record each drop of NaOH added to the beaker, so that you will know exactly how many drops of NaOH were required to cause the solution to change from clear and colorless to pale-pink in color. Next, carefully pour the solution down the sink drain and use the dish soap, tap water, and paper towels to wash and dry the beaker. Repeat, observe, and record. Next, add exactly 10 drops of NaOH from the pipet into the beaker containing the 4 mL of unknown. Gather a pH indicator strip from the kit and place it into the solution in the beaker so that all 4 indicator squares come into contact with the weak acid. Accurately read the pH indicator, record, and repeat. After finishing the experiment, calculate the percent error based on the results that was gathered throughout the experiment.

Exercise 1:

1. Using the data collected in Data Table 2, create a graph of “Drops of NaOH added” vs “pH” where “drops of NaOH added” is on the x-axis and “pH” is on the y-axis. Upload an image of the graph into Graph 1.

C:\Users\hall\Desktop\chart 1.jpg

2. pH indicator strips work by changing color in the presence of solutions with varied pH values. Thinking about your procedure steps and results in Part 1, why do you think the pH of the unknown weak acid was not determined with pH indicator strips until Part 2?

We use the pH indicator strips to calculate the amount of unknown acid in the receiving flask by measuring the specific amount of base it takes to neutralize the acid. There are two major ways to know when the solution has been fully neutralized. The first uses a pH meter in the beaker by slowly adding base until the pH reads exactly 7 (neutral). The next method uses a specific indicator. An indicator is an acid or base whose conjugate acid or base has a color difference from the original compound. The color changes when the solution contains a 1:1 ratio mixture of the differently colored forms of the indicator. The pH equals the p K a of the indicator at the endpoint of the indicator. Since the pH of the solution is known and the volume of titrate is added, we can then deduce how much base was needed to neutralize the unknown sample.

3. Discuss possible causes of error in the experimental procedure. Why do you think there was a percent of error in the pKa and Ka values of the unknown weak acid, in comparison to the values presented in Table 2?

My results were close with a 5% Ka error. This error could have come from the pH key, which may not have been 100 percent read precisely. Also, incorrect measuring of solutions when preparing the experiment could have resulted in error.

4. Do you think using a pH meter instead of pH indicator strips would have created a larger or smaller percent error? Explain your answer.

A pH meter has to be specifically calibrate correctly, so if this was calibrated incorrectly, it could also result in error, however I think that there would be a less of a percent error because a meter instrument is more accurate than strips and gives an exact numerical measurement.

5. Why was phenolphthalein a good indicator to use for determining the equivalence point between the unknown weak acid and strong base?

Phenolphthalein is a great indicator for determining the equivalence point. Is a suitable indicator for strong acid or a strong base. It is also a good indicator for a weak acid or strong base therefore it works well in this experiment.

Data Table 1: Determination of Equivalence Point

Trial 1

Trail 2

Volume of Unknown weak Acid

4ml

4ml

Total number of Drops required to reach equivalence point

114 required drops

104 required drops

Average Number of Drops

Average: 109

Data Table 2: Titration Curve Values

Drops NaOH added

pH Value Trial 1

pH Value Trail 2

pH Value Average

Half-Equivalent Point

54

54

5.0

Equivalent Point

109

109

0

3

1

1

10

2.5

2.5

2.5

20

3

3

3.25

30

3.5

3.5

4

40

4

4.5

4.25

50

4.5

5

4.75

60

5

5.5

5.5

70

6

6

6

80

6.5

6.5

6.5

90

7

7.25

7.5

100

7.5

7.5

7.75

110

8

8

8

120

11

11.5

12

Panel 1: Equivalent Point Number of Drops

The Equivalent Point= 93 Drops

Panel 2: Half- Equivalent Point Number of Drops

The Half- equivalent point= 46 Drops

Data Table 3: Determination of Unknown

pKa of Unknown Weak acid

5.0

Ka of Unknown Weak Acid

.00001

Unkown Weak Acid Identity

Acetic Acid

% Error pka

-44%

% error Ka

5%

C:\Users\hall\Desktop\4.jpg C:\Users\hall\Desktop\3.jpg C:\Users\hall\Desktop\pic 1.jpg C:\Users\hall\Desktop\3.jpg

Conclusion:

This lab demonstrated how a titration can be used to measure the concentration of an weak or strong acid or base in solution. This experiment allowed me to practice how to calculate the molar mass of an unknown acid or base, and determine the equilibrium constant of a weak acid (Ka) or weak base (Kb). By adding NaOH, a strong base, in small increments, it was possible to determine the equivalence point of NaOH and the unknown weak acid. Then, the pH at equilibrium was used in order to find the concentration of the unknown acid at equilibrium. In addition, by using the mass of the unknown weak acid and its concentration at equilibrium, the molar mass of the acid was determined. Finally, by using the equation pKa = -log(Ka) and the half equivalence point pKa, the value of Ka for the unknown weak acid was found.. Even though, I had a 5% error, I still believe I conducted this experiment to the best of my ability. I really enjoyed this lab and would recommend people to try it.

Homework is Completed By:

Writer Writer Name Amount Client Comments & Rating
Instant Homework Helper

ONLINE

Instant Homework Helper

$36

She helped me in last minute in a very reasonable price. She is a lifesaver, I got A+ grade in my homework, I will surely hire her again for my next assignments, Thumbs Up!

Order & Get This Solution Within 3 Hours in $25/Page

Custom Original Solution And Get A+ Grades

  • 100% Plagiarism Free
  • Proper APA/MLA/Harvard Referencing
  • Delivery in 3 Hours After Placing Order
  • Free Turnitin Report
  • Unlimited Revisions
  • Privacy Guaranteed

Order & Get This Solution Within 6 Hours in $20/Page

Custom Original Solution And Get A+ Grades

  • 100% Plagiarism Free
  • Proper APA/MLA/Harvard Referencing
  • Delivery in 6 Hours After Placing Order
  • Free Turnitin Report
  • Unlimited Revisions
  • Privacy Guaranteed

Order & Get This Solution Within 12 Hours in $15/Page

Custom Original Solution And Get A+ Grades

  • 100% Plagiarism Free
  • Proper APA/MLA/Harvard Referencing
  • Delivery in 12 Hours After Placing Order
  • Free Turnitin Report
  • Unlimited Revisions
  • Privacy Guaranteed

6 writers have sent their proposals to do this homework:

Academic Mentor
Writing Factory
24/7 Assignment Help
Top Writing Guru
Essay Writing Help
Top Rated Expert
Writer Writer Name Offer Chat
Academic Mentor

ONLINE

Academic Mentor

As an experienced writer, I have extensive experience in business writing, report writing, business profile writing, writing business reports and business plans for my clients.

$36 Chat With Writer
Writing Factory

ONLINE

Writing Factory

I can assist you in plagiarism free writing as I have already done several related projects of writing. I have a master qualification with 5 years’ experience in; Essay Writing, Case Study Writing, Report Writing.

$31 Chat With Writer
24/7 Assignment Help

ONLINE

24/7 Assignment Help

Being a Ph.D. in the Business field, I have been doing academic writing for the past 7 years and have a good command over writing research papers, essay, dissertations and all kinds of academic writing and proofreading.

$34 Chat With Writer
Top Writing Guru

ONLINE

Top Writing Guru

As per my knowledge I can assist you in writing a perfect Planning, Marketing Research, Business Pitches, Business Proposals, Business Feasibility Reports and Content within your given deadline and budget.

$42 Chat With Writer
Essay Writing Help

ONLINE

Essay Writing Help

I find your project quite stimulating and related to my profession. I can surely contribute you with your project.

$29 Chat With Writer
Top Rated Expert

ONLINE

Top Rated Expert

I am an academic and research writer with having an MBA degree in business and finance. I have written many business reports on several topics and am well aware of all academic referencing styles.

$33 Chat With Writer

Let our expert academic writers to help you in achieving a+ grades in your homework, assignment, quiz or exam.

Similar Homework Questions

Dog beach in rye - Greek for you a1 - Accrued interest income adjusting entry - Benchmark nonverbal communication training guide - Management of Employee Welfare &&&&& Management: Employee Discrimination - Survival of the sickest pdf free book - Minnesota micromotors simulation strategy solution - PS490 Assignment 4 - Logical and mathematical intelligence - Rolfe model of reflection essay - Challenge yourself 3.3 excel answers - Principle of justice in nursing - Phonics screening test 2014 - 100 mental maths starters - Poli 330 week 7 quiz - Strengths and weaknesses of professional bodies - Apex pro mxr 100 - Itm navi mumbai scholarship - Fox group holdings pty ltd - Polit and beck 2017 pdf - Understanding social meida - Write a paper, analyzing the role of the Nurse Practitioners in the prevention, early detection and treatment of SKIN DISORDERS. 2 pages APA - Electronic warfare fundamentals ppt - Which of the following are not true in reference to converting a basic disk to a dynamic disk? - What rainforest covers a large part of central africa - Time lags in fiscal policy - Why america is self segregating - Determining the ksp of calcium hydroxide lab report - Rationale for stress management - Wilkins a zurn company aggregate production planning solution - Answer questions - Module. 5 discussion - Pwr ie170w pc ac datasheet - Prince sports inc case study - Community Teaching Plan: Teaching Experience Paper - Section 20 1 the kingdom protista answer key - Big red combine harvester chords - Random Question. - Higher business past paper - $24 for ralibale - Discussion Oct 20th - Prepare a horizontal analysis of the balance sheet - Fluke 435 download data - 100v line speakers wiring - Alliteration examples for high school - Bd vacutainer order of draw - Forza t5 super strength - Discussion and Remove plagrism - Analyze paper - Light and heavy letters in arabic - Cool automatic watches that are sure fire conversation starters - The terrible fate of humpty dumpty script - 1.625 as a fraction - Deliverable 7 – 5500 Plan of Action - Phasor diagram synchronous generator - Data Leakage Research Paper - Compelled disclosure of individually identifiable information - Points to consider when choosing a seam - Shell canada fuels productivity with erp - Test for carbohydrates lab report discussion - Accuracy and precision worksheet chemistry - Helpyourmath sign in - Tesco extra pool jobs - Two scavengers in a truck bbc - Classification lab answer key - 3 miriam road denistone - Central phenomenon of the study - Socw 6456 - Jeff nippard push pull legs - Hyperbole examples in i have a dream speech - Disaster recovery plan team roles - DEBATE - Flow net diagram soil mechanics - Job rewards matrix - Human family maya angelou - Wpf mvvm entity framework - Crane load test procedure - Weebly chris fanini sup sup - Introduction to measurement lab answer key - Filming risk assessment form - What percentage is a 4 on the ap exam - Leave no trace minimize campfire impacts - Chemistry quiz on aleks - Ask uwa special consideration - Ato payg fortnightly tax table 2021 - Illuminated backlit container used in photography crossword - Ig solid wall lintel - Dicussion ( Principle of Economics) SJ Week 8 - Food safety problems and solutions essay - Http www bretwhissel net amortization amortize html - Reply 2 different discussions - Moderate effect smartart style - Partial year depreciation double declining balance - Vocabulary workshop level orange - Hippa: PowerPoint presentation - 10 minute micro teach ideas - Nutty sweet crossword clue - What type of innovation is the milo sensor wristband - Broen lab singapore pte ltd - It strategy and innovation mckeen pdf