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

Recrystallization theoretical yield

25/03/2021 Client: saad24vbs Deadline: 10 Days

Purifying Acetanilide by

Recrystallization

1. The solubility of benzoic acid in water is 6.80 g per 100 mL at 100°C and 0.34 g per 100 mL at 25°C.

Show your calculations for the questions below.

(a) Calculate the minimum volume of water needed to dissolve 1.00 g of benzoic acid at 100°C.

(b) Calculate the maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic

acid from 15 mL of water, assuming the solution is filtered at 25°C.

2. The solubility of acetanilide in your recrystallizing solvent is 5.0 mg per mL at 10°C. (10ºC is the

approximate temperature of an ice/water bath). Show your calculations for the questions below.

(a) Calculate the theoretical maximum percent recovery in this experiment, assuming a 15.0-mL

recrystallizing solution is filtered at 10°C.

(b) Calculate the percent recovery of the acetanilide produced in your experiment.

(c) How do your results compare to the theoretical maximum percent recovery? Explain any difference

you may have observed. Why is the theoretical maximum percent recovery (calculated in 2a above) not

necessarily applicable your experiment? Aside from technical or human error (such as spillage,

incomplete transfers, loss on the filter paper, loss due to excessive washing, etc.) or slight differences involume of solvent or temperature of the ice bath, what assumptions or estimations were made in this

calculation which may not apply to your results?

3. A student rushed through this experiment. Describe the effect that the following procedural changes

would have on the percent recovery of acetanilide; would the % recovery by higher, or lower? Briefly

explain the basis of each answer.

(a) Rather than adding 0.5-mL portions of boiling solvent to the acetanilide, the student added 5-mL

portions of boiling solvent.

(b) The student forgot to cool 5 mL of solvent in Part 4 and washed the crystals with room-temperature

solvent.

Separating Acids and Neutral Compounds by

Solvent Extraction

1. Based on the amounts of p-toluic acid and acetanilide you recovered, estimate the

composition of the original mixture, assuming that you lost equal amounts of each

compound. Show your calculations. Express the composition as percentages of each

component: For example “the original mixture was 30% p-toluic acid and 70%

acetanilide”.

2. What product would you obtain if you evaporated the water from the NaOH layer prior to

acidifying the layer?

3. Suppose that you used dichloromethane instead of diethyl ether as the nonpolar solvent in

this experiment. What changes in the procedure would you make in view of the fact that

dichloromethane is more dense than water?

4. Benzoic acid (C6H5—COOH) is a weak acid and naphthalene is neutral, neither acidic or

basic. Prepare a flowchart for the separation and recovery of benzoic acid and

naphthalene.

Benzoic Acid Naphthalene

solubility in water: poor solubility in water: poor

solubility in ether: good solubility in ether: good

5. After comparing the melting points of each of your compounds to their respective

literature values, comment on the purity of each compound. (You may skip this question if your

instructor did not have you acquire melting points).

O OH

1. Briefly describe the hazards you should be aware of when you work with:

(a) diethyl ether

(b) 3M HCl

2. Briefly explain or describe the following:

(a) How would you determine which layer is the aqueous layer after you add NaOH solution to

the ether solution of your compounds?

(c) What visible evidence(s) of reaction will you see when you acidify the NaOH extract with

HCl solution?

(d) In which layer would p-toluic acid be more soluble if p-toluic acid were added to a two-layer

mixture of diethyl ether and water?

13

Solvent Extraction, Pre-lab page 2

(e) How would the results differ if you added sodium p-toluate instead of p-toluic acid to the

two-layer mixture of diethyl ether and water?

4. How many milliliters of 3.0 M HCl would be required to neutralize 30. mL of 0.50 M

NaOH? (Show your work). (hint: this is a general chemistry question! Remember that the

acid HCl and the base NaOH react in a 1:1 molar ratio. The number of moles of acid need to

equal the number of moles of base to effect complete neutralization).

5. Briefly explain how you will isolate p-toluic acid after it is extracted it into NaOH solution.

6. Write the equation for the chemical reaction of the toluate ion that will occur when you

add HCl solution to the NaOH extract in part 3.

SN1 Reaction: A Kinetic study

Post-Laboratory Questions (attach your responses on a separate sheet)

1. From the experimental data, prepare a table of the following values. Record all calculated

results to the proper number of significant figures. Note that V and V¥ are the total volumes of

NaOH solution delivered; they are not burette readings (unless, of course, your initial buret

reading was 0.00 mL). Base your calculations on the actual value of V¥ that you measured in lab

- not the theoretical value! Time, t, is the elapsed time in seconds (its OK to use minutes if you

prefer). Use Equation 10 to calculate the values of k.

t (sec) V (mL) V/V¥ (1 - V/V¥) ln(1 - V/V¥) k

2. Prepare a graph of ln(1 – V/V¥) versus time, t. Using a computer program or a graphing

calculator, determine the best straight line through your data points. (See the supplement to this

lab for detailed instructions on how to determine best fit if you are unfamiliar with this process).

This graph should be properly labeled and drawn to scale. Do the data support the SN1

mechanism? Briefly explain.

3. Calculate the value of k from the slope of the line from the graph in 2.

4. Using the values of k which you determined above (in question #1), calculate the average

value of k, and estimate its uncertainty. One way to estimate its uncertainty is to

(1) calculate an average value of k

(2) calculate the absolute value of the deviation of each value from the average value

(3) calculate the average of these deviations.

Prepare a table which shows the deviation for each datum, and report the average value of k and

the average deviation. It may be convenient for you to include these data in the table you prepare

for post-lab question #1, above.

Note: What you are doing here is a standard statistical way of measuring reproducibility.

Theoretically, the value of k should be the same for all trials. In practice, however, you almost

certainly will observe some variation in the calculated values of k. The average deviation is a

way of expressing in a single number how much variability you have in your data. Low average

deviations mean your numbers are all close together; high average deviation means you have a

lot of “noise” or “scatter” in your data.

12

Pre-Laboratory Assignment SN1 Reaction: A Kinetic Study

Name ________________________________________________________________

Note: you may wish to copy this pre-lab before you submit it. (The results of pre-lab question

#2 will be helpful for your lab calculations).

1. Describe briefly the hazards associated with the reaction mixture and the safety precautions

you must take when performing the experiment.

2. Assume that you use 1.00 mL of 2-chloro-2-methylpropane. Calculate the following

quantities. Be sure to show your calculations; you will NOT receive credit if work is not

shown!

a. the number of moles of 2-chloro-2-methylpropane used. The density of the liquid is

0.851 g/mL.

b. the number of moles of HCl produced by complete solvolysis of 1.00 mL of 2-chloro-2-

methylpropane.

13

SN1 Reaction: A Kinetic Study, Pre-lab page 2

c. the volume in milliliters of 0.350 M NaOH required to neutralize the HCl produced by

complete solvolysis of 1.00 mL of 2-chloro-2-methylpropane. (This is referred to as V¥ in your

lab manual).

d. the volume in milliliters of 0.350M NaOH required to neutralize the HCI produced when

solvolysis of 1.00 mL of 2-chloro-2-methylpropane is 50% complete. (This is referred to

as V50% in your lab manual; the volume of base consumed when the reaction is 50%

complete).

Note: you may wish to record the values of V¥ and V50% separately before you turn in your

pre-laboratory assignment; you will need these values during the experiment.

Studying SN1 Reactions:

Nucleophilic Substitution at

Saturated Carbon

Post-Laboratory Questions

1. When you compared 2-bromo-2-methylpropane and 2-chloro-2-methylpropane (in part

one), what were the relative rates of the two reactions?

2. Based on your answer to question 1, which is the better leaving group, Br- or Cl- ?

HBr is a stronger acid than HCl. Are these results consistent with the relative

basicities of these two ions? Explain your answer.

3. Which compound, 2-bromo-2-methylpropane or 2-bromopropane, reacted faster in

your SN1 experiment? How are the reactivities of 2-bromo-2-methylpropane and

2-bromopropane related to the stabilities of the carbocations produced as intermediates in

the reaction? Explain your answer.

4. Which of the two solvent mixtures, 40% 2-propanol or 60% 2-propanol, is more

polar? Explain your answer.

5. In which of the two solvent mixtures did 2-bromo-2-methylpropane react faster?

Account for your results in terms of the effect of solvent polarity on the rate-determining

step in this SN1 reaction.

6. Use your results to explain which variable — leaving group, alkyl structure, or solvent

polarity — has the greatest impact on the rate of an SN1 reaction. In other words, which

variable had the most pronounced effect on the observed times?

9

Pre-Laboratory Assignment Studying SN1 reactions

Name _________________________________________________________________

1. Why do tertiary alkyl halides typically undergo SN1 substitution reactions more rapidly

than do primary or secondary alkyl halides?

2. Show a complete and balanced reaction for the solvolysis of

2-bromo-2-methylpropane in water. Also show a complete and balanced reaction for the

solvolysis of 2-bromopropane in water. (It is NOT necessary to show intermediates or

mechanisms, just the overall reactions). Which of these reactions is kinetically favored?

3. How does the SN1 reaction in this experiment cause the acid/base indicator,

phenolphthalein, to change color? Briefly explain.

10

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:

Accounting & Finance Mentor
Top Academic Guru
Top Essay Tutor
Homework Guru
Top Academic Tutor
ECFX Market
Writer Writer Name Offer Chat
Accounting & Finance Mentor

ONLINE

Accounting & Finance Mentor

You can award me any time as I am ready to start your project curiously. Waiting for your positive response. Thank you!

$28 Chat With Writer
Top Academic Guru

ONLINE

Top Academic Guru

I am known as Unrivaled Quality, Written to Standard, providing Plagiarism-free woork, and Always on Time

$106 Chat With Writer
Top Essay Tutor

ONLINE

Top Essay Tutor

I am known as Unrivaled Quality, Written to Standard, providing Plagiarism-free woork, and Always on Time

$64 Chat With Writer
Homework Guru

ONLINE

Homework Guru

Give me a chance, i will do this with my best efforts

$58 Chat With Writer
Top Academic Tutor

ONLINE

Top Academic Tutor

I have read and understood all your initial requirements, and I am very professional in this task.

$17 Chat With Writer
ECFX Market

ONLINE

ECFX Market

Hello, I an ranked top 10 freelancers in academic and contents writing. I can write and updated your personal statement with great quality and free of plagiarism

$44 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

John naisbitt megatrends 2000 - Instinctive drift psychology definition - Chern's case study - Essay - Quiz - Carinya residential windows and doors - Phone plans $0 upfront - Civilize them with a stick quizlet - Forum - Access chapter 2 grader project - Daimler and chrysler merger case study - Electricity meter box location requirements - To too and two - 3m ranger blood warmer set up - B737 air conditioning system - Homework Question - Acfi business rules 2017 - Gas shielded arc welding - Analytical essay due in 48 hours - 2-3pg. Critical response paper on The Odyssey, Translated by Robert Fitzgerald. ----Due 4pm 8/24/2020 - Miller corporation has a premium bond making - Sermon on the Mount Group Assignment - Angle questions and answers - What is an appositive - Fire rated cables australia - Troy dann outback adventures dvd - English 102 - Mansion house residential home - X 509 authentication service pdf - Desert eagle hypnotic rare pattern - How far is the closest black hole - Identify the electrophilic site in the following molecule - Pico questions for stroke patients - Discussion 6 - Concepts of human experience - Eight keys chapter summaries - The language you cry in - Carl rogers 6 conditions - Theory marketing partners - Www mysciencedoodles com water cycle - Writing the equation of a rational function given its graph - Report writing - Pediatric soap note - Tate and lyle maple syrup morrisons - Is humanity suicidal by edward o wilson - Errors commonly committed in a business letter - National university msn - Phd in it university of cumberlands - BIOLOGY - Infinite geometric series examples - English Essay - Community Nursing week 7 DQ 1 - Word chapter 1 grader project homework 3 project g - BUSINESS LAW, ETHICS AND SOCIAL RESPOSIBILITY - Portal systemic anastomosis definition - Management Fundamentals - Name five numbers between 0 and 1 - Hulu swot analysis - Week 2 case study supply and demand - Three components of the axial skeleton - Amisfield pinot noir 2012 - Looking at movies 6th edition by barsam and monahan - Case study on merger of vodafone and hutch pdf - Video questions the century 1953 1960 happy days answers - Family resources in home economics - Act 1 scene 3 summary othello - Fallout 4 elevator behind bookcase - Research Paper - Mass communication living in a media world sixth edition pdf - Modern database management pdf - The hate u give critical analysis - Fin - Creac legal writing example - Lorem, ipsum - Oakwood avenue primary school - Final project - Becoming nicole chapter 1 summary sparknotes - Alko iq7 xtreme wiring diagram - Virtual victorian negotiation planning document - Introduction to programming using python y daniel liang pdf - Warm up cool down pdhpe - Information gathered from observing a plant grow 3 cm - A man flies a small airplane from fargo to - Autozone inc case study - They say i say page 50 exercise 1 - Montgomery bank & trust ailey ga - Software project management plan - Instilling a corporate culture that promotes good strategy execution - Entrepreneurship owning your future study guide 6.1 answers - They say i say chapter 5 pdf - Assignment 2 situation analysis - Ku children's services pay rates - 1955 sw 5th ave portland or - Oceanservice noaa gov education tutorial currents welcome html - Wood pole mounting brackets - Zoonotic & Vector-borne Diseases SLA: Infographic - Stoichiometry lab vinegar and baking soda answer key - Utz better than nuts - Leccion 8 en el restaurante - Walt disney company mission statement 2017