| 1. | Safety |
| 2. |
Objectives/Overview |
| 3. |
Procedures |
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4. |
Observations |
| 5. | |
| 6. | |
| 7. | |
| 8. | Conclusions |
| 9. | Calculations/Set-Ups |
| 10. | Grading Scale |
| 11. | Review Prelab Questions |
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12. |
Review Postlab Questions |
Experiment
16
Chemical Equilibrium: Finding a Constant, Kc
PRE-LABOATORY QUESTIONS
References:
Brown, Lemay, and Bursten, Chemistry the Central Science, 8th ed.
(2000),
pp. 559-568 (chemical equilibrium)
pp. 576-580 (LeChatelier’s Principle)
Learning Center: answers to pre and post-lab questions.
1. At a particular temperature, a student determined that the equilibrium concentration of thiocyanatoiron(III) to be 1.01 x 10-4 M. For the same conditions, the [SCN1-] was calculated to be 6.99 x 10-4 M and [Fe3+] was 8.99 x 10-4 M Calculate Kc for the reaction:
Fe3+(aq) + SCN1-(aq) _ [Fe(SCN)]2+(aq)
2. At another temperature, Kc for the reaction is Problem 1 was found to be 172. At equilibrium, [Fe(SCN)2+]eq was determined to be 5.57 x 10-5 M, while [Fe3+]eq was calculated to be 9.44 x 10-4 M. Calculate the concentration of thiocyanate ion present at equilibrium.
