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lab is completed, the goal is to complete the lab_form using the lab image submitted.


Name Group Results 1. Qualitative examination of equilibria and Le Chatelier's Principle (20 pts) (You may scan and incorporate a pdf of your group’s data sheet.) Well # Contents (drops) Observations 1 Fe(NO3)3 [3] 2 KSCN [3] 3 Fe(NO3)3 [1]/KSCN [1] 4 Fe(NO3)3 [2]/KSCN [2] 5 Fe(NO3)3 [3]/KSCN [3] For 6-13 all wells start with: Fe(NO3)3 [3]/KSCN [3] 6 Distilled water [2] (control) 7 Fe(NO3)3 [2] 8 KSCN [2] 9 KSCN [4] 10 KSCN [1, 1M] 11 Na2HPO4 [2] 12 H2SO4 [2] 13 KSCN [1, 1M]/H2SO4 [3] For 14-18 materials are: 0.0025M Fe(NO3)3/ 0.1M HNO3/1M KSCN 14 As above 1/4/4 15 As above 2/3/4 16 As above 3/2/4 17 As above 4/1/4 18 As above 5/0/4 1. 2. Beer's Law Plot for the Absorbance of Fe(SCN)2+ (20 pts) (You may scan and incorporate a pdf of your group’s data sheet or include a pdf of your group’s Excel page.) Test Tube # [Fe3+]initial=[Fe(SCN)2+]eq A475 1 2 3 4 5 6 7 Slope of line (A475 vs. [Fe(SCN)2+]) = ε = 1. Absorbance measurements to determine the Equilibrium Constant (20 pts) Test Tube # [Fe(SCN)2+]eq A475 10 11 12 13 14 15 16 17 18 19 1. Calculation of the Equilibrium Constant Keq (called Kc in the text) (30 pts) Test Tube # [Fe3+]initial [SCN-]initial [FeSCN2+ ]eq [Fe3+ ]eq [SCN- ]eq keq 10 11 12 13 14 15 16 17 18 19 Average value for Keq = Questions (10 pts) · Explain in the context of Le Chatelier's Principle why it is mathematically acceptable to assume that the initial concentration of the iron (III) ion, [Fe3+], is equal to the equilibrium concentration of the complex ion, [FeSCN2-], for the Beer’s Law determination (Part 2). · If the class results for the were generally lower than the established value for Keq for this reaction, what might have caused the value to vary. This would seem to be a result of inaccuracies in the reported (labeled) concentrations of the reagents. What specific inaccuracies might have cause the generally lower values in the class results. Explain your answer. This is a mathematical question and requires a mathematical answer. Results 1 Qualitative examination of equilibria and Le Chatelier's Principle Well | Contents (drops) | Observations || FeO 3] Mo color chanse, clear Ligued 2 KSCN [3] No dor change, cleer isu d Fe(NOW: [1VKSCN 1] Solation Ained orange Fe(NOu): [2/KSCN [2] Fe(NOs)s [3YKSCN [3] Ugh orange gobo | Orange coludion For 6-13 all wells start with: Fe(NOy), [3/KSCN [3] Distilled water [2] (control) | chear—sobation 00 change gitubion EN ee HiS04 [2] 7 | Fe(NOs) [2] no change, solubim dx dae orange 8 Kscn) no change 9 | Kson fg no change 10 |Ksont, IM) B lukon changed dom ormnge Av Sn | NaHPOL [2] orange Ao des golden 2 oranse “ho cles Solution KSCN [1, IMJH:SO4 [3] orange to reddich-orange solubion Tor 14-18 materials are: 0.0025M Fe(NO3),/0-1M HNO IM KSCN As above 1/4/4 orange solukim 15 | Asabove 23/4 Ak cranae solakion 16 | Asabove 32/4 eMich orange soluion 17 | Asabove ana Jacle- vec. oranga_silotion 18 As above 5/0/4 ced solabm (deb) 2. Beer's Law Absorbance Data (Absorbance of Fe(SCN)™") Bring these data to my desk before continuing to Part 3. [Test Tube # | Ae 1 0.091 . 2 0-144 ~ [3 | omy | 4 0.248 } _ s 0-207 _ 6 0-460 . 7 0-55 3. Absorbance data to determine the Equilibrium Constant Do not expect these measurements to be linear. There is no need for me to see them during the lab. Test Tube # Asse 0 S¥ oma | mn oan 2 0-394 13 0-424 - 14 0.26% | 15 0-4dy 16 0.612 17 0.305 18 0386 Lr los |
Answered Same DayApr 16, 2024

Answer To: lab is completed, the goal is to complete the lab_form using the lab image submitted.

P answered on Apr 17 2024
8 Votes
Name                                    
Group             

Results
1. Qualitative examination of equilibria and Le Chatelier's Principle (20 pts)
(You may scan and incorporate a pdf of your group’s data sheet.)
    Well #
    Contents (drops)
    Observations
    
1
    
F
e(NO3)3 [3]
    No color change, clear liquid
    
2
    
KSCN [3]
    No color change, clear liquid
    
3
    
Fe(NO3)3 [1]/KSCN [1]
    Solution turned orange
    
4
    
Fe(NO3)3 [2]/KSCN [2]
    Light orange solution
    
5
    
Fe(NO3)3 [3]/KSCN [3]
    Orange solution
    
    For 6-13 all wells start with: Fe(NO3)3 [3]/KSCN [3]
    
    
6
    
Distilled water [2] (control)
    No change in solution, stayed orange
    
7
    
Fe(NO3)3 [2]
    No change, solution stayed orange
    
8
    
KSCN [2]
    No change
    
9
    
KSCN [4]
    No change
    
10
    
KSCN [1, 1M]
    Solution changed from orange to reddish orange/red
    
11
    
Na2HPO4 [2]
    Orange to clear solution
    
12
    
H2SO4 [2]
    Orange to clear solution
    
13
    
KSCN [1, 1M]/H2SO4 [3]
    Orange to reddish-orange solution
    
    For 14-18 materials are: 0.0025M Fe(NO3)3/
0.1M HNO3/1M KSCN
    
    
14
    
As above 1/4/4
    Orange solution
    
15
    
As above 2/3/4
    Dark orange solution
    
16
    
As above 3/2/4
    Reddish-orange solution
    
17
    
As above 4/1/4
    Dark-red orange solution
    
18
    
As above 5/0/4
    Red solution (dark)

1.
2. Beer's Law Plot for the Absorbance of Fe(SCN)2+ (20 pts)
(You may scan and incorporate a pdf of your group’s data sheet or include a pdf of your group’s Excel page.)
    Test Tube #
    
[Fe3+]initial=[Fe(SCN)2+]eq
    
A475
    
1
    
    0097
    
2
    
    0.149
    
3
    
    0.173
    
4
    
    0.248
    
5
    
    0.307
    
6
    
    0.460
    
7
    
    0.556
    Slope of line (A475 vs. [Fe(SCN)2+]) = ε =
    1
The slope represents the molar absorptivity coefficient.
Let's choose two points, say (0.097, A1) and (0.556, A7):
ε = (ΔA475) / (Δ[Fe(SCN)₂⁺])

ΔA475 = A7 - A1
Δ[Fe(SCN)₂⁺] = [Fe(SCN)₂⁺]₇ - [Fe(SCN)₂⁺]₁
Substitute the values:
ΔA475 = 0.556 - 0.097
= 0.459
Δ[Fe(SCN)₂⁺] = [Fe(SCN)₂⁺]₇ - [Fe(SCN)₂⁺]₁
= 0.556 - 0.097
= 0.459
Now, calculate the slope:
ε = ΔA475 / Δ[Fe(SCN)₂⁺]
= 0.459 / 0.459
= 1
So, the slope of the line (ε) for the Beer's Law plot is 1.
1. Absorbance measurements to determine the Equilibrium Constant (20 pts)
    Test Tube #
    
[Fe(SCN)2+]eq...
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