- Experiment 5 Determination Of An Equilibrium Constant Lab Report Sheet Note Many Of The Calculations Can Be Done Prior 1 (135.46 KiB) Viewed 13 times
- Experiment 5 Determination Of An Equilibrium Constant Lab Report Sheet Note Many Of The Calculations Can Be Done Prior 2 (93.07 KiB) Viewed 13 times
- Experiment 5 Determination Of An Equilibrium Constant Lab Report Sheet Note Many Of The Calculations Can Be Done Prior 3 (112.3 KiB) Viewed 13 times
- Experiment 5 Determination Of An Equilibrium Constant Lab Report Sheet Note Many Of The Calculations Can Be Done Prior 4 (93.56 KiB) Viewed 13 times
Experiment 5: Determination of an Equilibrium Constant Lab Report Sheet NOTE: Many of the calculations can be done prior to coming to lab, based on the concentrations and stoichiometry given in the introduction. It is strongly suggested you fill in as many calculations as possible before lab, and check their accuracy with your instructor. Experiment Objective What is the overall objective or purpose of these experiments? Answer in complete sentences. determine the The purpose was equilibrium constant using certain Chemicals balance the opposing forces A. Standard Solutions to Establish a Standardization Curve Molar Concentration of Fe(NO3)3 0.2 M Molar concentration of NaSCN 0.001m Standard Solutions Volume of NaSCN (mL) (See Table 5.1) Moles of SCN (M x L=mol) [SCN] (25.0 mL) (mol/0.025L) [FeNCS2] (mol/L) Absorbance, A Blank O O 1 0,00 1 1x10-6 2 2 3 -6 2х10 3.x10 3.x 10-6 S 8x10 3 4. X10 -S -S 4, ylos 8 x 10's 4 0.001 .001 5 4 5 4x10 Sx106 1.2 X104 1.6×104 2. X104 2x104/ 1.2 X101.6x104 0.21 0.45 0.72 0.96 1.24 0.00 0.21 0.45 0.72 0.96 1.21 38
Plot Absorbance vs [FeNCS2"] on graph paper or use a graphing program like Excel. Be sure to label each axis, title the graph, and ensure the straight line goes through the origin. B. Absorbance of the Test Solutions Test Solutions Volume of Fe(NO3)3 (mL)(Table 5.2-convert to L) Moles of Fe initial (Mx L=mol) Volume of NaSCN (mL) (Table 5.2- convert to L) Absorbance, A 6 0.005 0.005 0.005 7 0.12 Sample Calculation: (1) 8 1x 10³ 1×10³ 1 y 10³ 1x10³ 1x10 ²³ 0.12 -3 -3 3 3 1x 10³2x10³ 3x10³ 4x10³ 5x10² Зулоз -3 Moles of SCN, initial -4 (Mx L=mol) 2x10 4x104 6x104 8x 10-4 1×10-³ 9 0.00€ 0.47 0.47 10 0.43 0.57 0.43 XX 0.2 m y 0,07 = 0.014 0.57 0.59 0.59 IML = 0.001 L
C. Calculation of Ke Test Solutions [FeNCS], equilib from calibration curve [A] Moles FeNCS2+, at equilib (0.010 L) [Fe³+] at equilibrium Moles Fe³+, reacted (mol) (eq. 4) [C] Moles Fe³+, equilibrium (mol) from Table B [D] [Fe³+], equilibrium (unreacted) [E] [SCN] at equilibrium Moles SCN*, reacted (mol) (eq. 4-use values from B above) Moles SCN", Equilibrium (mol) from Table B [F] [SCN], equilibrium (unreacted) [G] 6 y=mx+b 7 x = y-b 8 9 10
Calculate K, for each solution using equation 3, K. = _ _[FeNCS²"] [Fe³¹][SCN] Solution 6: Solution 7: Solution 8: Solution 9: Solution 10: Average Kc: Concluding Questions: 1. Why do we calibrate the spectrophotometer with 0.2 M Fe(NO3)3 diluted with 0.1 M HNO3 instead of 0.2 M Fe(NO3)3 diluted with deionized water? To balance absorption using the will give us than deionized water. 2. For preparing a set of standard solutions of FeNCS2+, the equilibrium molar concentration of FeNCS2+ is assumed to be equal to the initial molar concentration of the SCN in the reaction mixture. Why is this assumption valid? the blank a more Chemicals, spectrophot number rather due to measurment. The accurate. 41