Average absorbance, Molarity of Fe(NO₂)), 0.2M Volume of Fe(NO₂)) = 5.00mL Moles of FeMolarityx Molarity x volume(L) Moles of Fe=0.2Mx0.005L=10"mole moles of Fe Concentration of Feolume 500 x 10-1000M 10 mole 9 +0.128 +0.127)/3 = 0.129 hrome .png Fe"]= Fe³"]=0.002mol/L nown concentrations to determine (FeSCN"]at equilibrium in solution 8: Y = 4290X -0.068 [SCN"]= X= QQ 100% 0.127=4290X-0.068 (0.127 +0.068) 4290 = 4.5 x 10-5mol/L 25ml Fe³* x 0.002 mol/L-¹ 100ml 20ml SCN" x 0.002 mol/L-1 100ml 5.00 x 10^4 mol/L^-1 4.00 x 10 mol/L-1 = Flask 8 Flask 9 Flask 10 Flask 11 4.png Part 3: Q Flank & Flask 9 Flank 10 Flask 11 Part 3:09 Flask Flank Flask 10 Flask 11 Ⓒ (Fes* (mol/L) 5.00 x 10 5.00 x 104 5.00 x 10 5.00 x 104 Average absorbance 0.127 0.166 0.222 6.308 100% (FESC mol/L) 4.5 × 10-5 5.4 x 10 8.76 x 10 DX [SCN~](mol/L) 4.00 x 10-4 4x10* 7x 10-4 1x 10-3 Place the results from calculations 9 and 10 into individual ICE tables. Calculate the equilibrium concentration of Feland SCN-in solutions 8 to 11. a) Calculate K, for each solution using the results of calculations 9 and 11. Calculate the average value of K b) One published value of Ke for the equilibrium system under consideration is 146 at room temperature (Journal of Chemical Education, 75. pp 90). Determine a percent error for your average calculated value of K, based on this literature value. TABLE 2-COMPOSITION OF SOLUTIONS REQUIRED FOR CALCULATION OF EQUILIBRIUM CONSTANT Volume of 0.002 mol L Volume of 0.002 mol L Flask # Fe(NO3)2(aq) /ml. KSCN[ar) / mk 7 (blank) 8 9 10 11 25.00 25.00 25.00 25.00 25.00 0.00 20.00 25.00 35.00 50.00 Ensure your Thermo Scientific Spectronic 200 spectrophotometer is powered on so that it is warmed up by the time you use it later in the procedure. Pipette 5.00 mL of 0.2 mol L4 Fe(NO)(aq) into a clean 500-mL volumetric flask. Fill the flask carefully to the calibration mark with 1.0 mol L HNO3(aq). stopper it, and mix well by inversion (25 times). Pour about 175 mL of the solution you just prepared into a clean, dry 250-ml beaker. The concentration of Fe(NO:):(aq) in this solution is approximately 0.002 mol L-4 Pipette the required volumes of 0.002 mol L4 Fe(NO3)(aq) and then 0.002 mol L-4 KSCN(aq) into five clean. labelled 100-ml volumetric flasks. Before using the 25-ml pipette to deliver KSCN(aq) solution, remember to rinse it with this solution three times to remove any traces of Fe(NO1)(aq) that might be in it. Fill the flasks precisely to the calibration marks with deionized water. Remove any water droplets above the marks with a Kimwipe. Stopper the flask and mix each thoroughly by inverting it 25 times.

Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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g
2.png
Average absorbance,
.129 +0.128 +0.127)/3 = 0.128
Chrome
Concentration of Females of Fe
volume
Q
Molarity of Fe(NO₂)) = 0.2M
Volume of Fe(NO₂)); = 5.00mL
Moles of Fe³+= Molarity x Molarity x volume(L)
Moles of Fe³* = 0.2M x 0.0054 = 10³mole
10-mole
500 x 10-3=0.002M
[Fe³+] =
[SCN¯] =
X =
✪
[Fe³] = 0.002mol/L
nknown concentrations to determine [FeSCN]at equilibrium in solution 8:
Y = 4290X - 0.068
72%
(0.127 + 0.068)
4290
0.127=4290X - 0.068
25ml Fe³+ x 0.002 mol/L-¹
100mL
100%
= 4.5 x 10-5mol/L
20ml SCN X 0.002 mol/L-¹
100mL
= 5.00 x 10^4 mol/L^-1
= 4.00 x 10 mol/L-1
W
Flask 8
Flask 9
Flask 10
Flask 11
3.png
4.png
Part 3: Q8
Flask 8
Flask 9
Flask 10
Flask 11
Part 3: 09
Flask 8
Flask 9
Flask 10
Flask 11
[Fe³+ (mol/L)
5.00 x 10-4
5.00 x 10-4
5.00 x 10-4
5.00 x 10-4
Average absorbance
0.127
0.166
0.222
69%
0.308
100%
[FESCN¹ (mol/L)
4.5 x 10-
5.4 x 10
6.76 x 10-5
8.76 x 10-
[SCN (mol/L)
4.00 x 10-4
4 x 10-4
7 x 10-4
1x 10-³
3
7.png
Place the results from calculations 9 and 10 into individual ICE tables. Calculate the equilibrium concentration of
Fe³+ and SCN-in solutions 8 to 11.
7 (blank)
8
9
✪
a) Calculate K, for each solution using the results of calculations 9 and 11. Calculate the average value of K.
b) One published value of K, for the equilibrium system under consideration is 146 at room temperature (Journal
of Chemical Education, 75. pp 90). Determine a percent error for your average calculated value of K, based on this
literature value.
TABLE 2-COMPOSITION OF SOLUTIONS REQUIRED FOR CALCULATION OF EQUILIBRIUM CONSTANT
Volume of 0.002 mol L
Volume of 0.002 mol L
Flask #
Fe(NO3)3(aq) / ml.
KSCN(aq) / ml
10
11
69%
25.00
25.00
25.00
25.00
25.00
0.00
20.00
25.00
0
35.00
50.00
Ensure your Thermo Scientific Spectronic 200 spectrophotometer is powered on so that it is warmed up by the
time you use it later in the procedure.
Pipette 5.00 mL of 0.2 mol L4 Fe(NO3)3(aq) into a clean 500-mL volumetric flask. Fill the flask carefully to the
calibration mark with 1.0 mol L-¹ HNO3(aq), stopper it, and mix well by inversion (25 times). Pour about 175 mL
of the solution you just prepared into a clean. dry 250-mL beaker. The concentration of Fe(NO:):(aq) in this
solution is approximately 0.002 mol L-4.
Pipette the required volumes of 0.002 mol L-1 Fe(NO3)(aq) and then 0.002 mol L-4 KSCN(aq) into five clean,
labelled 100-mL volumetric flasks. Before using the 25-mL pipette to deliver KSCN(aq) solution, remember to rinse
it with this solution three times to remove any traces of Fe(NO3)(aq) that might be in it.
Fill the flasks precisely to the calibration marks with deionized water. Remove any water droplets above the marks
with a Kimwipe. Stopper the flask and mix each thoroughly by inverting it 25 times.
Measure the absorbance of the solutions in flasks 8 through 11 as outlined in part 3 of the procedure.
Transcribed Image Text:g 2.png Average absorbance, .129 +0.128 +0.127)/3 = 0.128 Chrome Concentration of Females of Fe volume Q Molarity of Fe(NO₂)) = 0.2M Volume of Fe(NO₂)); = 5.00mL Moles of Fe³+= Molarity x Molarity x volume(L) Moles of Fe³* = 0.2M x 0.0054 = 10³mole 10-mole 500 x 10-3=0.002M [Fe³+] = [SCN¯] = X = ✪ [Fe³] = 0.002mol/L nknown concentrations to determine [FeSCN]at equilibrium in solution 8: Y = 4290X - 0.068 72% (0.127 + 0.068) 4290 0.127=4290X - 0.068 25ml Fe³+ x 0.002 mol/L-¹ 100mL 100% = 4.5 x 10-5mol/L 20ml SCN X 0.002 mol/L-¹ 100mL = 5.00 x 10^4 mol/L^-1 = 4.00 x 10 mol/L-1 W Flask 8 Flask 9 Flask 10 Flask 11 3.png 4.png Part 3: Q8 Flask 8 Flask 9 Flask 10 Flask 11 Part 3: 09 Flask 8 Flask 9 Flask 10 Flask 11 [Fe³+ (mol/L) 5.00 x 10-4 5.00 x 10-4 5.00 x 10-4 5.00 x 10-4 Average absorbance 0.127 0.166 0.222 69% 0.308 100% [FESCN¹ (mol/L) 4.5 x 10- 5.4 x 10 6.76 x 10-5 8.76 x 10- [SCN (mol/L) 4.00 x 10-4 4 x 10-4 7 x 10-4 1x 10-³ 3 7.png Place the results from calculations 9 and 10 into individual ICE tables. Calculate the equilibrium concentration of Fe³+ and SCN-in solutions 8 to 11. 7 (blank) 8 9 ✪ a) Calculate K, for each solution using the results of calculations 9 and 11. Calculate the average value of K. b) One published value of K, for the equilibrium system under consideration is 146 at room temperature (Journal of Chemical Education, 75. pp 90). Determine a percent error for your average calculated value of K, based on this literature value. TABLE 2-COMPOSITION OF SOLUTIONS REQUIRED FOR CALCULATION OF EQUILIBRIUM CONSTANT Volume of 0.002 mol L Volume of 0.002 mol L Flask # Fe(NO3)3(aq) / ml. KSCN(aq) / ml 10 11 69% 25.00 25.00 25.00 25.00 25.00 0.00 20.00 25.00 0 35.00 50.00 Ensure your Thermo Scientific Spectronic 200 spectrophotometer is powered on so that it is warmed up by the time you use it later in the procedure. Pipette 5.00 mL of 0.2 mol L4 Fe(NO3)3(aq) into a clean 500-mL volumetric flask. Fill the flask carefully to the calibration mark with 1.0 mol L-¹ HNO3(aq), stopper it, and mix well by inversion (25 times). Pour about 175 mL of the solution you just prepared into a clean. dry 250-mL beaker. The concentration of Fe(NO:):(aq) in this solution is approximately 0.002 mol L-4. Pipette the required volumes of 0.002 mol L-1 Fe(NO3)(aq) and then 0.002 mol L-4 KSCN(aq) into five clean, labelled 100-mL volumetric flasks. Before using the 25-mL pipette to deliver KSCN(aq) solution, remember to rinse it with this solution three times to remove any traces of Fe(NO3)(aq) that might be in it. Fill the flasks precisely to the calibration marks with deionized water. Remove any water droplets above the marks with a Kimwipe. Stopper the flask and mix each thoroughly by inverting it 25 times. Measure the absorbance of the solutions in flasks 8 through 11 as outlined in part 3 of the procedure.
Expert Solution
Step 1

The balanced equation for the equilibrium reaction is:

Fe3+(aq) + SCN-(aq)  Fe(SCN)2+(aq) ; K = ??

The equilibrium constant expression is:

K = [Fe(SCN)2+]eq[Fe3+]eq * [SCN-]eq

So we have to find the equilibrium concentrations for Fe(SCN)2+(aq), Fe3+(aq) , and SCN-(aq)

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