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

Sources of error in ph lab

08/12/2021 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:

University Coursework Help
Coursework Assignment Help
Engineering Mentor
Finance Master
Custom Coursework Service
Top Writing Guru
Writer Writer Name Offer Chat
University Coursework Help

ONLINE

University Coursework Help

I will be delighted to work on your project. As an experienced writer, I can provide you top quality, well researched, concise and error-free work within your provided deadline at very reasonable prices.

$46 Chat With Writer
Coursework Assignment Help

ONLINE

Coursework 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.

$49 Chat With Writer
Engineering Mentor

ONLINE

Engineering Mentor

I have read your project details and I can provide you QUALITY WORK within your given timeline and budget.

$43 Chat With Writer
Finance Master

ONLINE

Finance Master

I have written research reports, assignments, thesis, research proposals, and dissertations for different level students and on different subjects.

$21 Chat With Writer
Custom Coursework Service

ONLINE

Custom Coursework Service

After reading your project details, I feel myself as the best option for you to fulfill this project with 100 percent perfection.

$22 Chat With Writer
Top Writing Guru

ONLINE

Top Writing Guru

I have done dissertations, thesis, reports related to these topics, and I cover all the CHAPTERS accordingly and provide proper updates on the project.

$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

Under what type of marketing does kliptech operate - What were two causes of the great depression - Tell them not to kill me - Robinhood vision statement - Philosophy discussion - 2016 physics exam solutions - Virtul psy - Integrating sources activity - Ron popeil dead or alive - Project team design plan - D11 HRM - Bg 66 ultimax tension - Boxes with clear lids wholesale - Fifo and lifo costs under perpetual inventory system - Victimology Annotated Bibliography - Inverse trigonometric functions table - Discussion - Rising sun movies mareeba - Memo on wastage of stationery - Ari weinzweig and paul saginaw illustrate that good leadership is - Assignment 350 words - Pumpkin acidic or alkaline - Dissertation Topic for Cloud Computing 300-400 words - Hey buddy can you spare a dime worksheet answers - Factor comparison job evaluation - Family therapy history theory and practice 6th edition - Bus 520 leadership and organizational behavior - Lonnie russ something old something new lyrics - Excel year 5 pdf - Legal-v assignment - How to curate wikis on amino - Paul von lettow vorbeck hitler - Physiological adaptations to cardiovascular exercise - A cat corp forecasting case solution - 300 words - What is a first order consumer - Sweet leaf bath co marketing report - Grade 5 scoring sampler passage set and prompt - Connected mcgraw hill school c3p0 - Audrey dawns character based on middlemen - Information technology in global Economy - Genius gluten free pain au chocolat - What clinical findings correlate with mk s chronic bronchitis - American Dream - HR PC - Privacy Rights - Nicomachean ethics book 1 pdf - Physics final exam review - Pronombres de objeto directo e indirecto en español - My crew my dogs set rules set laws lyrics - Carine senior high school map - Psychotherapy and legal implications - Matlab state space simulation - Concordia college jobs bronxville - How to write an executive summary for a hospital - Designing team and team identity in team management - For Dr isaac Maths - Easylap panel installation guide - Benchmark - Policy Brief - Research Question, Problem Statement, Research Purpose - Rubbish chute hire brisbane - Essay(Interview a Muslim) - I need help for capsim - Value sensitive design and information systems - Operational excellence assignment week 7 - Jason statham great yarmouth - Have fun teaching alphabet song - How to do a cage analysis - Toughness jay bilas chapter summary - Habitable zones lab answers - Percent acetic acid in vinegar lab - Religious study, reflection paper4 - Healthwoods endoscopy centre granville - A boy's best friend isaac asimov questions and answers pdf - Medicare levy surcharge reportable fringe benefits - Mathswatch clip 94 answers - Coralline algae scientific name - Four lenses of wellness - A _______ is often used to cut holes to install outlet boxes in old installations. - Virtual event sponsorship - Open shut them give a little clap prayer - Math - Counseling treatment plan template word - Eng 125 comformity - Panera bread core competencies - Infinite monkey theorem pte answer - Peanut company acquired 100 percent of snoopy company's outstanding - Business discussion - Gauging the extent to which marketing objectives have been achieved - Neis allowance rate 2021 - Edexcel biology grade boundaries - The key operating question of moral management is - Wadsworth college reading series book 2 answers - War prayer by mark twain summary - Pepsi cola code of ethics - Group assignment - Is wayne williams still in jail - Data Mining Project - Peter boxall university of auckland - Impact of bantu migration