question archive Answer Questions: Experiment: Equilibrium Constant 4 Question Need to be Answer 1- Using your data from the mixtures in test tubes 1, 3, and 5 of Part 2, recalculate three new equilibrium constants with the new possible reaction below
Answer Questions: Experiment: Equilibrium Constant 4 Question Need to be Answer 1- Using your data from the mixtures in test tubes 1, 3, and 5 of Part 2, recalculate three new equilibrium constants with the new possible reaction below
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Answer Questions: Experiment: Equilibrium Constant 4 Question Need to be Answer 1- Using your data from the mixtures in test tubes 1, 3, and 5 of Part 2, recalculate three new equilibrium constants with the new possible reaction below. What are the three new equilibrium constants? (10 pts) You have been told that the reaction you are observing is: Fe3+(aq) + SCN– (aq) ? FeSCN2+(aq) Another possibility is that the reaction is: Fe3+(aq) + 2 SCN– (aq) ? Fe(SCN)2 + (aq) ***Hint: Notice that the change in concentration of SCN– in your equilibrium table will change because of the new stoichiometry. Also, the exponent on [SCN– ] in the equilibrium constant expression will change for the same reason. 2- In Part 1 of this experiment, you assumed that the FeSCN2+ concentrations in your standard solutions were equal to the initial concentrations of SCNions. Now that you know the value of the equilibrium constant, calculate the actual equilibrium concentrations of Fe3+, SCN- , and FeSCN2+ in the mixture in test tube 2. Compare the values for the [FeSCN2+]. Are there any significant differences? Why or why not? (10 pts) ***HINT: Since you know the initial concentrations of your reactants, and you know Kc – you can now solve for the equilibrium concentrations using an ICE table rather than a Limiting Reagent Table. Your Kc is large, not small; therefore, you cannot use the small x-approximation. You must solve the quadratic equation. Remember: One value of x will make more sense than the other. 3- Write Data & Results for each tables (Tables are appropriately labeled (each correctly identified, appropriate title, and units are included. Required figures are also included.) 4- write Analysis (Includes a separately labeled section with an explanation of results, trends, and what they mean.) Part 1 Tables Composition of solutions for preparing the calibration curve: Volume of 0.20 M F(NO3)3 in 1 M HNO3 (mL) 5.0 5.0 5.0 Test Tube 1 2 3 Volume of 2.00 x 10^-3 M KSCN (mL) 0.50 1.0 1.5 Volume of DI water (mL) 4.5 4.0 3.5 Final Volume Test Tube Abs at 447nm [FeSCN2+] [M] 1 0.413 0.0001 2 0.799 0.0002 3 1.175 0.0003 Value of Epsilon (ε) = 3119M^-1cm^-1 10 10 10 Part 2 Tables Composition of solutions for determining the equilibrium constant: Volume of 2.00 x 10^-3 Volume of 2.00 Volume of Test Final M Fe(NO3)3 in 1 M x 10^-3 M DI water Tube Volume HNO3 (mL) KSCN (mL) (mL) 1 5.0 1.0 4.0 10 2 5.0 2.0 3.0 10 3 5.0 3.0 2.0 10 4 5.0 4.0 1.0 10 5 5.0 5.0 0 10 Test Tube Abs at 447 nm Actual Wavelength 1 0.005 447.6 2 0.041 447.6 3 0.129 447.6 4 0.149 447.6 5 0.162 447.6 5 Test Tubes (Part 2 Tables). Test tube 1: R I C E Reaction Initial Concentration (M) Change in Concentration (M) Equilibrium Concentration (M) Fe3+ 1× 10^-3 -1 × 10^-6 9.99 × 10^-4 SCN2× 10^-4 -1 × 10^-6 1.99 × 10^4 FeSCN2+ 0 +1 × 10^-6 1 × 10^-6 Test tube 2: R I C E Reaction Initial Concentration (M) Change in Concentration (M) Equilibrium Concentration (M) Fe3+ 1×10^-3 -1.64 × 10^5 9.836 × 10^4 SCN4 × 10^4 -1.64 × 10^5 3.836 × 10^4 FeSCN2+ 0 +1.64 × 10^5 1.64 × 10^-5 Test tube 3: R I C E Reaction Initial Concentration (M) Change in Concentration (M) Equilibrium Concentration (M) Fe3+ 1×10^-3 -7.74 × 10^5 9.226 × 10^4 SCN6 × 10^-4 -7.74 × 10^5 5.226 × 10^4 FeSCN2+ 0 +7.74 × 10^5 7.74 × 10^-5 Test tube 4: R I C E Reaction Initial Concentration (M) Change in Concentration (M) Equilibrium Concentration (M) Fe3+ 1×10^-3 -1.192 × 10^-4 8.808 × 10^4 SCN8 × 10^-4 -1.192 × 10^-4 6.808 × 10^4 FeSCN2+ 0 +1.192 × 10^4 1.192 × 10^-4 Test tube 5: R I C E Reaction Initial Concentration (M) Change in Concentration (M) Equilibrium Concentration (M) Fe3+ 1×10^-3 -1.62×10^-4 SCN1×10^-3 -1.62×10^-4 FeSCN2+ 0 +1.62×10^-4 8.38×10^-4 8.38×10^-4 1.62×10^-4 Calculated Equilibrium Constants: Test Tube Kc 1 4.834 2 20.4 3 44.236 4 38.29 5 33.128 Average 28.17
