1CHM2123_2022_Chemoselectivity_Report
pdf
keyboard_arrow_up
School
University of Ottawa *
*We aren’t endorsed by this school
Course
2123
Subject
Chemistry
Date
Feb 20, 2024
Type
Pages
25
Uploaded by ProfessorBisonMaster407
CHM 2123 — Laboratory Report Fall 2022 Planning ahead – The impact of experimental conditions on a reaction’s outcome Student(s) Name(s) and Number(s) : This report is: Date: Teaching Assistant: Weekly Lab Period COMMENTS •
Your report is submitted electronically via
Brightspace
into the dedicated folder. •
This report can be completed individually or in pairs, with your assigned lab partner, to each student’s preference. If done in pairs, each student must submit an identical copy of the pre-lab. Make sure to include both your names and student numbers above. Both students will receive the same marks and comments. •
This lab report is due on the week of November 14
th
, by the beginning of your respective lab section
. Do not trust Brightspace’s due date: since every students share the same Brightspace page, the due date found online is for the last section of the week. •
Your results and discussion will cover both reactions done for this experiment. Type all the answers using Arial font, size 12 pt, directly in the cells provided. The cells are representative of the length of the expected answer, and their sizes have been locked to discourage superfluously long answers. Anything exceeding this expected length may be ignored by the TA.
•
Molecular figures must be drawn using ChemDraw.
•
Late penalty is 20%/day, starting the moment the report is due and going up every 24h. Point distribution Introduction and Experimental Section /8 Results and Observations /15 Discussion /45 Post-Lab Question /19 Conclusion /5 Appendix /2 TOTAL /94
Introduction and Experimental Section Explain briefly, and in your words
, the objectives of this experiment, and a short description of the procedure and techniques employed to achieve your goal. This description should include your initial hypothesis regarding the identity of the products as well as (if relevant) the purpose of the various reagents used. In addition, explain how the relevance of the key steps. (
8 pts
)
The goal of this experiment was to dive into the chemoselectivity that 4-methoxyactophenone has in acidic and basic conditions. I did not write a hypothesis however, I would have said that product 4 would have been produced in basic conditions, and product 7 would have been produced in acidic conditions. The competition of the reactions was tested by TLC plates to determine whether a reaction had to proceed longer if there were any starting materials present. The acidic reaction included stirring 4-methoxyactophenone, acetic acid, and bleach until reaction was completed, when was filtered by vacuum filtration once reaction was deemed complete. To purify the acidic product, the crude sample was then recrystallized using 1:1 methanol and water. To test the final acidic product’s purity, TLC and melting point analysis were used. For the basic conditions, 4-methoxyactophenone, bleach, and NaOH were put into a reflux and put in a liquid-liquid extraction once the reaction was deemed complete by the TLC plate. 2 washes off ethyl acetate was used to separate the product, and the aqueous layer was then put in an ice bath and dried with a water aspirator. The basic product as well was tested with TLC and melting point analysis to determine purity and identity. To determine whether the products produced were the expected products by comparing the results to IR and NMR spectroscopy. The new products will have new functional groups that will look differently on IR and NMR spectroscopy and will raise the melting point dramatically. The stereochemistry comes into play when talking about where the functional groups will be added. For the acidic reaction, the regioselectivity will produce the major product the most, which will be the most stable or reachable position for the chloride group to be. For the basic reaction, the regioselectivity will produce the major product the most, which will be the most stable or reachable position for the OH group to be.
Results and Observations Provide a point-form list of meaningful visual
observations made for each reaction, including the purification steps. For each observation, briefly explain how this observation is relevant to the reaction at hand. (
4 pts
) Acidic conditions Basic conditions •
Solution was clear, then became yellow as bleach was added: an intermediate was produced •
While stirring, solution became brown then purple with yellow precipitate forming at the bottom: the final product was produced •
Dark yellow solid after being filtered: final product isolated •
When solid was heating with 1:1 methanol and water, solution turned dark yellow: solid dissolved into solution •
Final recrystallized solution was a dark yellow solid •
Solution was clear through reflux •
Organic layer was clear, and aqueous layer was light yellow during liquid-
liquid extraction: shows the separation of organic and aqueous •
Solution became a slurry with white precipitate: charged final product produced •
Blue litmus paper turned red once solution when HCl was added: acidified the solution •
Final filtered product was a white powder Based on the identity of each product, fill the following tables. (
5 pts
) Product’s molar mass Product’s molar mass Compound Mass (g) mmoles Compound Mass (g) mmoles 4-Methoxyacetophenone (Acidic Rxn)
1.10 7.33 4-Methoxyacetophenone (Basic Rxn)
0.60 4.00 Crude A
1.76 9.53 Purified B
1.07 7.03 Recrystallized A
0.81 4.39 Final yield (%) 60% Final yield (%)
176%
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Using ChemDraw, replicate the key TLC results obtained throughout the experiment, which should include: •
the starting 4-methoxyacetophenone, both final reaction mixtures, the recrystallized product of the acidic reaction and the dried product of the basic reaction. Label all relevant details on your drawings. On the drawing (or alternatively in table form), list all of the measured distances and R
f
for all spots observed, along with their respective colors, if any. (
4 pts
)
4M = 4- methoxyacetophenone A = acidic reaction (testing to see if reaction completed) B = basic reaction (testing to see if reaction completed) BF = final basic product AC = acidic crude product AF = acidic final product (recrystallized) ** The Rf value 0.58 corresponds to 4M in the bottom left TLC, the spot migrated on the plate. Note the melting point ranges measured for each product: (
2 pts
) Recrystallized A (acid reaction): 58.1
o
C – 60.2
o
C Purified B (base reaction): 196
o
C – 200
o
C (melting point apparatus said OL once temperature hit 200
o
C) R
f
= 0.56
R
f
= 0.47
R
f
= 0.06
R
f
= 0.46
R
f
= 0.56
R
f
= 0.20
R
f
= 0.44
R
f
= 0.62
R
f
= 0.80
1: 3 Ethyl Acetate/Hexanes
1: 3 Ethyl Acetate/Hexanes
1: 3 Ethyl Acetate/Hexanes
1: 3 Ethyl Acetate/Hexanes
4M
A
B
AF
AC
4M
4M
4M
BF
Discussion 1) The IR spectrum for product A (acidic reaction) can be found in Appendix 1. Which of the molecule(s) could potentially produce this spectrum? Identify the relevant vibrations (present or absent) that can help you narrow down the list of possible products. (
2 pts
) Molecule 7 or 5: aromatic ring at 1600-1430 cm
-1
, C=O stretch at 1780-1650 cm
-1
, and C-
O stretch at 1250-1050 cm
-1
2) The NMR spectrum for product A
can be found in Appendix 2. Complete the table below in decreasing order of chemical shift. (
There are more rows than necessary: you may delete the extraneous rows.
). In the space provided, draw the corresponding molecule, and label all equivalent hydrogen nuclei with the corresponding Hydrogen Atom Label
from the table. (An example is provided on Brightspace.) (
5 pts
) Product’s structure Hydrogen Atom Label Chemical Shift (ppm) Multiplicity Integration Comments a 2.5 S 3H CH3-C=O b 3.95 S 3H CH3-O c 6.95 D 1H H-Aromatic ring d 7.80 D 1H H-Aromatic ring e 7.88 S 1H H-Aromatic ring You may use the space below to further explain your rationale in explaining your assignment for each signal. O
CH
3
O
H
3
C
a
Cl
H
H
H
d
c
b
e
3) The IR spectrum for product B (basic reaction) can be found in Appendix 3. Which of the molecule(s) could potentially produce this spectrum? Identify the relevant vibrations (present or absent) that can help you narrow down the list of possible products. (
2 pts
) Molecule 4: aromatic ring at 1600-1430 cm
-1
, O-H stretch at 2500 – 3000 cm
-1
. 4) The NMR spectrum for product B
can be found in Appendix 4. Complete the table below in decreasing order of chemical shift. (
There are more rows than necessary: you may delete the extraneous rows.
). In the space provided, draw the corresponding molecule, and label all equivalent hydrogen nuclei with the corresponding Hydrogen Atom Label
from the table. (An example is provided on Brightspace.) (
4 pts
) Product’s structure Hydrogen Atom Label Chemical Shift (ppm) Multiplicity Integration Comments a 3.9 S 3H OH-carboxyl b 6.8 D 2H H-Aromatic ring c 8.0 D 2H H-Aromatic ring d 12.2 S 1H CH3-O You may use the space below to further explain your rationale in explaining your assignment for each signal. O
OH
O
H
3
C
H
H
a
b
c
d
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
5) a) Remind the reader of your initial prediction regarding the TLC characterization results for both of your reactions. (
i.e
. How did you predict that the R
f
of the products would behave in regards to the starting 4-methoxyacetophenone?) How do your results compare to this prediction? (
1 pt
) Although I did not do the prelab, I would have predicted that the formed product would have a lower R
f
value than the starting material since it would have more hydrogen donating potential (making it more polar). As shown if my TLC, the formed product was in fact more polar than my starting material, resulting in a lower R
f
. b) Are the TLC results obtained for both final products (in comparison to the starting material) that you have prepared consistent with the spectroscopic results provided? Why/why not? (
3 pts
) The TLC results obtained for both final products were consistent with the spectroscopic results provided. The R
f
value of the formed basic product was greatly less than the starting material, which is expected because of the OH group. The OH group makes the molecular more polar, resulting in a lower R
f value, and the OH group can be found on the NMR spectrum for the basic reaction. Additionally, the R
f
value for the formed acidic product was lower than the starting material because of the chloride on the benzene. The chloride makes the molecule more polar, resulting in a lower R
f
value, and the chloride can also be seen on the NMR spectrum for the acidic reaction. 6) a) Remind the reader of your initial prediction regarding the m.p. characterization results for both of your reactions. (
i.e
. How did you predict the melting point of the product would behave in regards to the starting 4-methoxyacetophenone). How do your results compare to this prediction? (
1 pt
) I would have predicted that the melting point for both of my reactions to have a greater melting point that the starting materials because my expected products both have a stronger intermolecular substituent (chloride and OH group). Since they both would have stronger intermolecular forces, the melting point would be higher, which they both were.
b) Compared to the starting material (m.p.≈38°C), are the melting point results for both final products that you have prepared consistent with the spectroscopic results inferred so far? Why/why not? (
3 pts
) For both the basic and acidic reactions, the melting point results were consistent with the spectroscopic results. The basic reaction resulted in a much higher melting point than the starting materials, and that can be accounted for by the OH group. The starting material didn’t have much intermolecular forces because of a lack of strong functional groups, resulting in a low melting point. The OH group greatly impacted the intermolecular forces and raised the melting point a lot, and the OH group can once again be accounted for on the NMR spectrum for the basic reaction. The acidic reaction’s melting point did also go up, just not as greatly as the basic’s reaction. The chloride did create stronger intermolecular forces which elevated the melting point, but the chloride group isn’t strong enough to impact the melting point as much as the basic. The chloride group can also be accounted for on the NMR spectrum for the acidic reaction. 7) Was your initial hypothesis correct or not? (Which products were you expecting for each reaction? Which products did you actually obtain?) Are all the data in agreement with your conclusion? (
2 pts
) Once again, I did not propose a hypothesis, but I would’ve hypothesized that product 4 would be produced for the acidic reaction and product 7 would be produced for the basic reaction. Therefore, all my results point that this hypothesis is correct. The products were confirmed by the melting point, the IR, and the NMR spectrum. 8) What is the oxidation state of the various atoms in hypochlorous acid? What does this tell us about the reactivity of the atoms in hypochlorous acid? (
2 pts
) In hypochlorous acid, chlorine’s oxidation state is +1, oxygen’s oxidation state is -2, and hydrogen’s oxidation state is +1. Oxygen can donate 2 electrons easily, and hydrogen and chloride can receive 1 electron to form a bond easily.
9) a) What type of transformation occurred between 4-methoxyacetophenone and bleach in acidic conditions? (
Hint: This is a reaction that you would have seen in CHM1321). For both starting materials, identify the nucleophile and the electrophile, making sure to highlight the reactive position in each reagent. (
2 pts
) The type of transformation that occurred between 4-methoxyacetophenone and bleach in acidic conditions is electrophilic aromatic substitution. The oxygen on the 4-
methoxyacetophenone acts as a nucleophile and the bleach acts as an electrophile. b) Provide a mechanism for the reaction in acid conditions. (
3 pts
)
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
10) “
It’s a regioselective reaction
” you overheard a TA say while discussing the acidic reaction. What does that mean? What makes this reaction regioselective? (
2 pts
) Regioselectivity is when one product will be produced more than another, since it is more referred than another. A regioselective reaction can yield in two products, giving a major and minor product, the major being the more stable or more accessible product formed. The Cl atom can be added onto multiple positions, resulting in different products, regioselectivity will produce the major product more, which is molecule 7. 11) a) Draw the likeliest acid-base reaction to occur between 4-methoxyacetophenone and sodium hypochlorite. Identify the approximate ratio of reagents/products at equilibrium. Explain your answer. (
3 pts
) Ratio of product/reagent: 2/1 b) What is the difference in reactivity between 4-methoxyacetophenone and its corresponding conjugate species (which is formed upon reaction with sodium hypochlorite); are they more likely to accept or donate electrons? (
1 pt
) The conjugate species is more likely to react and donate electrons since it has a negative charge of the oxygen, and 4-methoxyacetophenone is neutral on the oxygen. c) The two products of the acid-base reaction described in a) can further react together. Based on your answers in both b) and question 8, draw the likeliest reaction to happen here. (
Hint
: The product of this reaction is an intermediate on route to product B
). (
1 pt
) O
O
NaOCl
O
O
HOCl
d) The intermediate in c) can further react twice through similar reactions as seen in a/c). What are the two new intermediates formed? These subsequent reactions are each more favorable than the previous one; why? (
2 pts
) These reactions are more favorable then the previous because they are less stable molecules, resulting in them being more reactive and therefore are more favorable to proceed the reaction. e) What needs to happen to go from the second intermediate in d) to the final product B
? Take into account the reagents available. (
1 pts
) There would need to be an excess of bleach O
O
HOCl
O
O
Cl
OH
12) Based on your own experimental results, were the respective products of each reaction of good purity? Explain your answer. (
5 pts
) I would say the respective products of each reaction had good purity. All of my TLC plates had only one spot in the lane when testing the reaction, which indicates that there were no other molecules presents besides my target product. As well, my Rf values did prove that I produced more polar compounds for both reactions, a sign showing that it is possible I created the correct compounds. My melting point analysis was nearly perfect, with the expected acidic melting point to be 55-85
o
C and getting 58.1
o
C – 60.2
o
C. The expected acidic melting point was 180-210
o
C and my product’s melting point was roughly 196
o
C – 200
o
C. Post-Lab Questions 13) Provide an approximate pK
a
for the hydrogens highlighted in red. Some of these molecules can be quantitatively deprotonated in water; for these molecules, indicate the pH ranges required to ensure a full deprotonation. (
5 pts
) Molecule Approximate pK
a
pH range a 2.0 4-5 b 7.5 13-14 c 11.5 6 d 4.75 8-9 e 45 2 14) Refluxing the acidic reaction will lead to the formation of a side-product, as witnessed in TLC by the appearance of a new spot whose R
f
is intermediate to that of the starting material and the major product.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
a) In the left cell, draw the structure of this side-product. How would you expect the melting point of this side-product to compare to the target product? Explain your answer. (
2 pts
)
I would expect the melting point to be greater than the melting point of the target product. This side-product has 3 chloride groups opposed to just one chloride group found in the target product, which would raise the melting point significantly. b) You were able to separate and purify both the product and this side-product. How would you distinguish the two using IR and NMR spectroscopies, so as to figure out which is which? Be specific in terms of what signals could be used for your analysis on either techniques. (
2 pts
)
The side product would only have 3 hydrogen signals present rather than 5 hydrogen signals the on the NMR spectrum since there are more chlorides placed where hydrogens were. Additionally, the C-H stretch would not be as intense on the IR spectrum since there’s only 3 sp3 hydrogens bonded rather than 6. O
O
Cl
Cl
Cl
15) Draw a flowchart showcasing the purification step done for the reaction under basic conditions, starting from the crude reaction mixture all the way to the isolated solid product. Assume for this drawing that there are still traces of your starting material in the crude mixture, along with any possible excess reagents. (
4 pts
) O
OH
O
O
H2O and ETOAc
O
O
O
O
Aqueous
Organic
Aqueous
Organic
O
O
O
O
HCl
ETOAc
O
OH
O
Water Aspiration
Filtraion
O
OH
O
16) Describe how optical polarimetry could had been of use for this experiment. (
1 pt
)
Optical polarimetry could have been used as an identity analysis on the final products to see if the expected product was produced. Since each molecule has a specific rotation value, the product can be directly compared to the expected product and see if it matches. 17) You have the four following molecules isolated in their pure state in unlabelled vials. How would you distinguish each using only an IR spectrometer? Be specific in terms of what signals could be used for your analysis. (
3 pts
)
A: C=O stretch at 1715 cm
-1
, broad O-H stretch at 3300 cm
-1
B: C-H stretch at 3010 cm
-1
, C=C stretch at 1620 cm
-1
, C=O stretch at 1700 cm
-1
, C-O stretch at 1250 cm
-1
C: C-H stretch at 3250 cm
-1
, C
≡
C at 2250 cm
-1
, O-H stretch from 3400 cm
-1
– 2500 cm
-1
D: C-H stretch at 3010 cm
-1
, C=C stretch at 1610 cm
-1
, broad O-H stretch at 3300 cm
-1
, C-
H at 2800 cm
-1
and 2700 cm
-1
, C=O stretch at 1700 cm
-1
18) During the heating phase of the recrystallization of A
, oily droplets are observed: heat and solvent must be provided until these droplets fully disappear. What are the droplets, and why must they disappear? Discuss this observation in the context of the properties of the solid being purified and the recrystallization solvent used. (
2 pts
)
The droplets are 4-Methoxybenzoic acid “oiling out” in solution, and they must disappear to fully be dissolved into the solution to be recrystallized out. A reason why this might have occurred is because there are impurities in the crude sample that are lowering the melting point, so it has a melting point lower than the solvent’s temperature. The impurities often dissolved better in droplets than in the solvent, resulting to be “oiling out”.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Conclusion Briefly remind the reader of the goal of the experiment, your initial hypothesis, the outcome of the experiment, and key evidence to support your conclusion. (
5 pts
) The goal of this experiment was to determine which stereospecific molecule will be produced from 4-methoxyactophenone in both acidic and basic conditions. Molecule 4 being produced for basic conditions was my hypothesis, which I proved right majorly because my expected acidic melting point was 55-85
o
C and my product’s melting point was 58.1
o
C – 60.2
o
C. Molecule 7 being produced for acidic conditions was my hypothesis and ehe expected acidic melting point was 180-210
o
C and my product’s melting point was roughly 196
o
C – 200
o
C. The stability of the functional groups allows for these products to be the major products produced in either condition and the melting point changes so much since the intermolecular forces are getting stronger with the new functional groups. Overall, I would deem this experiment a successful in both producing the expected product, but also having pure enough product to be able to directly compare my results to the IR and NMR spectroscopy. Appendix Include a single photo showcasing all of your relevant TLC plates. The photo must be done under UV irradiation, and the upper right corner of your plate(s) must be labelled with the initials of both team members. (
2 pts
)
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Appendix 1
– IR spectrum of product A
(acidic reaction)
. The inset shows a zoom-in on the low wavenumbers region.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Appendix 2
– H NMR spectrum of product A
(acidic reaction). Numbers in red represent the relative integrations of the signals. Insets correspond to zoom-in on regions of interest.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Appendix 3
– IR spectrum of product B
(basic reaction)
. The inset shows a zoom-in on the low wavenumbers region.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Appendix 4
– H NMR spectrum of product B
(basic reaction). Numbers in red represent the relative integrations of the signals. Insets correspond to zoom-in on regions of interest.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Related Questions
Please don't provide handwritten solution ....
arrow_forward
Products purchased from grocery stores are dated and need to be used within a certain amount of time. This is to protect consumers from the effects of food spoilage. Which process helps to slow the spoilage of food products?
arrow_forward
Name (please print):
Fall 2022
Basic Laboratory Operations
Post Lab Questions
1.) Suppose you're attempting to measure the density of a liquid that is highly volatile (it evaporates
quickly). If you first measure the mass and then several minutes later you measure the volume of the
liquid will the measured density be higher than the true value, lower than the true value, or the true
density of the liquid. [It helps to understand this problem with the density equation.]
2.) Suppose you're attempting to measure the density of a liquid that is highly volatile (it evaporates
quickly). If you first measure the volume and then several minutes later you measure the mass of the
liquid will the measured density be higher than the true value, lower than the true value, or the true
density of the liquid. [It helps to understand this problem with the density equation.]
3.) You're attempting to calculate the density of an alloy. The alloy is in the shape of a cylinder. If the
mass of the alloy is…
arrow_forward
Use your experiment rate law and the average value for k to predict how long (in seconds)it would take for the acetone iodination reaction to finish for the initial conditions givenbelow. Note that you are solving for Δt in the average reaction rate.initial concentrations: [acetone] = 0.850 M[H+] = 0.320 M[I2] = 0.00150 Mreaction time (seconds): ______________How precise were the experimental measurements of the reaction time for each reactionmixture? How precise were the measurements of the value of the rate constant, k? Explain your answers.
arrow_forward
Introduction to Integrated Rate Laws
Learning Goal:
To understand how to use integrated rate laws to solve for concentration.
A car starts at mile marker 145 on a highway and drives at 55 mi/hr in the direction of
decreasing marker numbers. What mile marker will the car reach after 2 hours?
This problem can easily be solved by calculating how far the car travels and
subtracting that distance from the starting marker of 145.
55 mi/hr x 2 hr = 110 miles traveled
milemarker 145 -110 miles milemarker 35
If we were to write a formula for this calculation, we might express it as follows:
milemarkero- (speed x time)
milemarker
where milemarker is the current milemarker and milemarker, is the initial
milemarker.
Similarly, the integrated rate law for a zero-order reaction is expressed as follows:
[A]orate x time
[A]
or
since
rate k[A] = k
Azero-order reaction (Figure 1)proceeds uniformly over time. In other words, the rate
does not change as the reactant concentration changes. In contrast,…
arrow_forward
Name: Lyna Ammi
Date: 1/26/2022 Section: 02L
Data Report Sheet: The Reaction of Methyl Violet with NaOH: A Kinetic
Study
3. What is the value of k"?
arrow_forward
What are limitations and improvements in this experiment and source of errors
arrow_forward
11:08 1
Question 23 of 25
Submit
Construct the expression Kc for the following
reaction.
2 P(s) + 5 Cl2(g) = 2 PCI;(g)
1
Drag the tiles into the numerator or
denominator to form the expression.
K. =
5 RESET
[P]
[Cl.]
[PCIg]
2[P]
5[Cl_]
2[PCI;]
[P]?
[PCIs]?
2[P]?
5[Cl_]$
2[PCIs]?
arrow_forward
Based on your ICE table (Part 2) and the definition of Ka, set up the expression for Ka in
order to determine the unknown. Each reaction participant must be represented by one
tile. Do not combine terms.
Ka =
2.9 × 10-8
RESET
[0]
(0.13]
[0.37]
(0.010]
[0.040]
[0.10]
[0.40]
[x]
[2x]
[0.13 + x)
[0.13-x]
[0.010+x]
[0.010-x]
[0.040 + x] [0.040 - x]
[0.10+x]
[0.10-x]
[0.40+x]
[0.40-x]
PREV
2
Based on your ICE table (Part 2) and the equilibrium expression for Ka (Part 3),
determine the pH of solution.
pH =
RESET
0
7.3 × 10*
5.86
18.74
1.4 × 10+
0.13
8.14
0.89
arrow_forward
Please see attached photo.
arrow_forward
the mean time, the rate,
[S₂O3] in the reaction
may label clear outliers
the mean) as such and
e calculation.
on mixtures
NH4)2SO4 (NH4)2S2O8|
(mL)
(mL)
1.50
0.50
1.50
0.50
1.00
1.00
1.00
1.00
following reagents are
um iodide
ium persulfate
m thiosulfate
um nitrate
ium sulfate
odide in the solution in the
Answer: 0.050 M
• Determination of the rate law follows the protocol in ref.
(5). with one difference. A reactant order (rate law
exponent) will be calculated twice using two different
pairs of determinations (e.g. determinations 1 & 2 and
determinations 3 & 4). Then the mean is taken of both
values and reported as order. This is done for each
reactant. This additional step allows us to include more
data and reduce experimental error.
Practice Problem 2: The rate of a reaction
CO(g) +3H₂(g)→ CH4(g) + H₂O(g)
was determined at 25 °C. From the following data,
determine
a) the mean reaction order with respect to CO
b) the mean reaction order with respect to H₂
c) the overall rate order
d)…
arrow_forward
За.
Bromine and methanoic acid react in aqueous solution.
Br, (aq) + HCO0Н (ад) — 2Br (aq) + 2H" (аq) + Со, (g)
The reaction was monitored by measuring the volume of carbon dioxide produced as time
progressed.
o 5 10 15 20 25
[Source: © International Baccalaureate Organization 2019]
30
20
40
60
80
100
120
140
160
Time / s
[Source: © International Baccalaureate Organization 2019]
Determine from the graph the rate of reaction at 20 s, in cm³ s1, showing your working.
3b.
Outline, with a reason, another property that could be monitored to measure the rate of this
reaction.
3c.
Describe one systematic error associated with the use of the gas syringe, and how the error
affects the calculated rate.
3d.
Identify one error associated with the use of an accurate stopwatch.
Volume of carbon dioxide / cm
T m mm mo
arrow_forward
Can you please help me with this?
arrow_forward
B IU Av A
1. Using the Ideal Gas Law (PV = nRT), calculate the grams of O2 produced in the reaction. Show
%3D
your work and follow the steps below.
If you pressure is not yet in atm, convert it to atm using the appropriate conversion factor.
b. Convert the volume of oxygen collected from mL to L.
C.
Convert the temperature of the water from °C to K.
d. Plug in P, V, R (gas constant), and T to the ideal gas law and solve for n, which is moles of
oxygen gas.
e. Use the moles of oxygen gas found and the molar mass of O2 to calculate the grams of
oxygen produced using dimensional analysis.
arrow_forward
When fitting data to a best fit line, a correlation coefficient (R2) is determined and
used to evaluate the quality of fit. The best fit of the data will have an R² value
closest or equal to zero (0).
closest or equal to one (1).
equal to the rate of the reaction occurring.
equal to the rate constant of the reaction occurring.
arrow_forward
1. This question is adapted from Harris 19-D.
Carnosine is a dipeptide whose antioxidant properties protect cells from free radicals. Carnosine was
determined by derivatization with naphthalene-2,3-dicarboxyaldehyde and cyanide followed by
fluorescence detection using excitation at 445 nm and emission at 490. Quantification was by standard
addition. To four aliquots of 20-ul cell lysate were added volumes of 100µM carnosine standard to
generate final concentrations of 0, 1.0, 2.5, and 5.0 µM added carnosine. Solutions were diluted to 70µl
before addition of 15µl of 5 mM naphthalene-2,3-dicarboxyaldehyde and 15µl of 10 mM NaCN.
H
H2N.
OH
Carnosine
HN.
Naphthalene-2,3-
dicarboxyaldehyde
Cyanide
OH
Fluorescent product
HN.
Fluorescence intensity
Concentration (uM) of added carnosine
in final 100 µL
0.0
0.465
1.0
0.698
2.5
1.029
5.0
1.651
arrow_forward
3. The decomposition of N2O5 in the gas phase was studied at constant temperature,
2N2O5 (g) → 4NO2 (g) + O2(g)
The following results were collected:
find
nature)
N2O5]
0.1000
Ln[N2O5]
-2.30
2.65
2.99
-3.69
-4.38
-5.08
a. Complete the table. Using the data and graph paper, plot the [N2O5] versus time and
Time (s)
10g.
(LN)
0.0707
0.0500
50
0.0250
100
0.0125
200
0.00625
300
400
Ln[N2O5] versus time. Determine the value of k. Which graph did
you use?
graph
*b. On your graph of [N2O5] versus time, highlight the times it takes for each halving of
the reactant concentration. What is the half-life? Using this half-life calculate k.
design experiments to find the activation energy,
arrow_forward
what is m and n
arrow_forward
8.
Consider the reaction:
Trial #
1
2
3
4
5
6
2NH (g) + 302(g) + 2CH(g) → 2 HCN(g) + 6H₂O(g)
[CH₂] (M)
0.37
0.45
0.45
0.26
0.45
0.17
[NH)] (M)
0.035
0.035
0.054
0.054
0.054
0.079
c. Write the rate law.
b. Determine the overall reaction order.
[0₂] (M)
0.12
0.27
0.12
0.27
a. Determine the order with respect to each of the reactants.
0.27
0.32
d. Solve for the value of the rate constant with units.
Rate M/hr
2.3 x 10²
1.6 x 102
5.5 x 10²
3.7 x 102
3.7 x 10²
arrow_forward
SEE MORE QUESTIONS
Recommended textbooks for you
Organic Chemistry: A Guided Inquiry
Chemistry
ISBN:9780618974122
Author:Andrei Straumanis
Publisher:Cengage Learning
Chemistry: The Molecular Science
Chemistry
ISBN:9781285199047
Author:John W. Moore, Conrad L. Stanitski
Publisher:Cengage Learning
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Related Questions
- Please don't provide handwritten solution ....arrow_forwardProducts purchased from grocery stores are dated and need to be used within a certain amount of time. This is to protect consumers from the effects of food spoilage. Which process helps to slow the spoilage of food products?arrow_forwardName (please print): Fall 2022 Basic Laboratory Operations Post Lab Questions 1.) Suppose you're attempting to measure the density of a liquid that is highly volatile (it evaporates quickly). If you first measure the mass and then several minutes later you measure the volume of the liquid will the measured density be higher than the true value, lower than the true value, or the true density of the liquid. [It helps to understand this problem with the density equation.] 2.) Suppose you're attempting to measure the density of a liquid that is highly volatile (it evaporates quickly). If you first measure the volume and then several minutes later you measure the mass of the liquid will the measured density be higher than the true value, lower than the true value, or the true density of the liquid. [It helps to understand this problem with the density equation.] 3.) You're attempting to calculate the density of an alloy. The alloy is in the shape of a cylinder. If the mass of the alloy is…arrow_forward
- Use your experiment rate law and the average value for k to predict how long (in seconds)it would take for the acetone iodination reaction to finish for the initial conditions givenbelow. Note that you are solving for Δt in the average reaction rate.initial concentrations: [acetone] = 0.850 M[H+] = 0.320 M[I2] = 0.00150 Mreaction time (seconds): ______________How precise were the experimental measurements of the reaction time for each reactionmixture? How precise were the measurements of the value of the rate constant, k? Explain your answers.arrow_forwardIntroduction to Integrated Rate Laws Learning Goal: To understand how to use integrated rate laws to solve for concentration. A car starts at mile marker 145 on a highway and drives at 55 mi/hr in the direction of decreasing marker numbers. What mile marker will the car reach after 2 hours? This problem can easily be solved by calculating how far the car travels and subtracting that distance from the starting marker of 145. 55 mi/hr x 2 hr = 110 miles traveled milemarker 145 -110 miles milemarker 35 If we were to write a formula for this calculation, we might express it as follows: milemarkero- (speed x time) milemarker where milemarker is the current milemarker and milemarker, is the initial milemarker. Similarly, the integrated rate law for a zero-order reaction is expressed as follows: [A]orate x time [A] or since rate k[A] = k Azero-order reaction (Figure 1)proceeds uniformly over time. In other words, the rate does not change as the reactant concentration changes. In contrast,…arrow_forwardName: Lyna Ammi Date: 1/26/2022 Section: 02L Data Report Sheet: The Reaction of Methyl Violet with NaOH: A Kinetic Study 3. What is the value of k"?arrow_forward
- What are limitations and improvements in this experiment and source of errorsarrow_forward11:08 1 Question 23 of 25 Submit Construct the expression Kc for the following reaction. 2 P(s) + 5 Cl2(g) = 2 PCI;(g) 1 Drag the tiles into the numerator or denominator to form the expression. K. = 5 RESET [P] [Cl.] [PCIg] 2[P] 5[Cl_] 2[PCI;] [P]? [PCIs]? 2[P]? 5[Cl_]$ 2[PCIs]?arrow_forwardBased on your ICE table (Part 2) and the definition of Ka, set up the expression for Ka in order to determine the unknown. Each reaction participant must be represented by one tile. Do not combine terms. Ka = 2.9 × 10-8 RESET [0] (0.13] [0.37] (0.010] [0.040] [0.10] [0.40] [x] [2x] [0.13 + x) [0.13-x] [0.010+x] [0.010-x] [0.040 + x] [0.040 - x] [0.10+x] [0.10-x] [0.40+x] [0.40-x] PREV 2 Based on your ICE table (Part 2) and the equilibrium expression for Ka (Part 3), determine the pH of solution. pH = RESET 0 7.3 × 10* 5.86 18.74 1.4 × 10+ 0.13 8.14 0.89arrow_forward
- Please see attached photo.arrow_forwardthe mean time, the rate, [S₂O3] in the reaction may label clear outliers the mean) as such and e calculation. on mixtures NH4)2SO4 (NH4)2S2O8| (mL) (mL) 1.50 0.50 1.50 0.50 1.00 1.00 1.00 1.00 following reagents are um iodide ium persulfate m thiosulfate um nitrate ium sulfate odide in the solution in the Answer: 0.050 M • Determination of the rate law follows the protocol in ref. (5). with one difference. A reactant order (rate law exponent) will be calculated twice using two different pairs of determinations (e.g. determinations 1 & 2 and determinations 3 & 4). Then the mean is taken of both values and reported as order. This is done for each reactant. This additional step allows us to include more data and reduce experimental error. Practice Problem 2: The rate of a reaction CO(g) +3H₂(g)→ CH4(g) + H₂O(g) was determined at 25 °C. From the following data, determine a) the mean reaction order with respect to CO b) the mean reaction order with respect to H₂ c) the overall rate order d)…arrow_forwardЗа. Bromine and methanoic acid react in aqueous solution. Br, (aq) + HCO0Н (ад) — 2Br (aq) + 2H" (аq) + Со, (g) The reaction was monitored by measuring the volume of carbon dioxide produced as time progressed. o 5 10 15 20 25 [Source: © International Baccalaureate Organization 2019] 30 20 40 60 80 100 120 140 160 Time / s [Source: © International Baccalaureate Organization 2019] Determine from the graph the rate of reaction at 20 s, in cm³ s1, showing your working. 3b. Outline, with a reason, another property that could be monitored to measure the rate of this reaction. 3c. Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate. 3d. Identify one error associated with the use of an accurate stopwatch. Volume of carbon dioxide / cm T m mm moarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage LearningChemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning
Organic Chemistry: A Guided Inquiry
Chemistry
ISBN:9780618974122
Author:Andrei Straumanis
Publisher:Cengage Learning
Chemistry: The Molecular Science
Chemistry
ISBN:9781285199047
Author:John W. Moore, Conrad L. Stanitski
Publisher:Cengage Learning
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning