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.

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 for Engineering Students

4th Edition

ISBN:9781337398909

Author:Lawrence S. Brown, Tom Holme

Publisher:Lawrence S. Brown, Tom Holme

Chapter4: Stoichiometry

Section: Chapter Questions

Problem 4.98PAE

See similar textbooks