EXPT. 34 EQUILIBRUIM.docx - Experiment 34 An Equilibrium...

This preview shows page 1 - 4 out of 8 pages.

Experiment 34: An Equilibrium Constant Lab Partner(s): Laura & Jocelyn General Chemistry II Section DA3 Date of Experiment: October 1, 2018 Hypothesis: If the slope equation is calculated from the absorbance vs. molar concentration of FeNCS 2+ graph (calibration curve), then the moles of Fe 3+ and SCN - can also be determined to find the equilibrium constant (K c ) of the chemical equation. Materials and Methods Please refer to Experiment X on pages X-X of Laboratory Manual for Principles of General Chemistry by J. A. Beran (10 th Ed.). There were no deviations from the published procedure 1
Results and Data: An Equilibrium Constant A Set of Standard Solutions to Establish a Standardization Curve Molar Concentration of Fe (NO 3 ) 3 ( mol/L ) 0.2 (~0.2 M ) Molar Concentration of NaSCN (mol/L ) 0.001 (~0.001 M) 2
Data Plot appears below and on Sheet 2 Standard Solutions Blank 1 2 3 4 Volume of NaSCN ( mL ) Moles of SCN - ( mol ) 0.00 1.00E-06 2.00E-06 3.00E-06 4.00E-06 [SCN - ] (25 mL) ( mol/L ) 25.00 25.00 25.00 25.00 25.00 [FeNCS 2+ ] ( mol/L ) 0.00 4.00E-05 8.00E-05 1.20E-04 1.60E-04 Percent Transmittance, % T Absorbance, A 0.00 0.15 0.21 0.27 0.49 Absorbance for the Set of Test Solutions Molar Concentration of Fe (NO 3 ) 3 ( mol/L ) 0.002 (~0.002 M) Molar Concentration of NaSCN ( mol/L ) 0.002 (~0.002 M) Test Solutions 6 7 8 9 10 Volume of Fe (NO 3 ) 3 ( mL ) 5 5 5 5 5 Moles of Fe 3+ , initial ( mol ) 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05 Volume of NaSCN ( mL ) 1.00 2.00 3.00 4.00 5.00 Moles of SCN - , initial ( mol ) 2.00E-06 4.00E-06 6.00E-06 8.00E-06 1.00E-05 Percent Transmittance, % T Absorbance, A 0.09 0.15 0.22 0.32 0.37 Calculation of K c [FeNCS 2+ ], equilibrium, from Calibration Curve ( mol/L ) 3.17E-05 5.25E-05 7.36E-05 1.10E-04 1.55E-04 Moles FeNCS 2+ , at equilibrium (10 mL) ( mol ) 3.17E-07 5.25E-07 7.36E-07 1.10E-06 1.55E-06 [Fe 3+ ], equilibrium Moles Fe 3+ , reacted ( mol ) 3.17E-07 5.25E-07 7.36E-07 1.10E-06 1.55E-06 Moles Fe 3+ , unreacted ( mol ) 9.68E-06 9.48E-06 9.26E-06 8.90E-06 8.45E-06 [Fe 3+

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture