Answer to Question #172587 in General Chemistry for sdadsa

Question

Le Chatelier’s Principle Lab

In this experiment, iron (III) (Fe3+) reacts with thiocyanate ion (SCN-) to form the deep red complex ion, FeSCN2+. The intensity of the red color will tell you if [FeSCN2+] changes.

• Do your observations support your prediction based on Le Chatelier’s Principle? Explain using color observations (Evidence)
• Explain the direction equilibrium shifted for each activity in this lab. Explain why shifted that direction?
• Based on the color change you observe, is the equilibrium for the solution in the ice water shifting left or right?
• Based on the color change you observe, is the equilibrium for the solution in the hot water shifting left or right?
• Do your observations indicate that the reaction is exothermic or endothermic? That is, based on your observations, is heat a product or a reactant? How do you know?
• What is the net ionic equation of this reaction with heat included in the equation?
• Are equilibrium shifts reversible? Justify using evidence from the lab.

Answer 1

Adding thiocyanate ion back into solution caused the equilibrium to shift back to the right. The solutions that received potassium phosphate were observed to fade and become yellow. When the iron ion concentration was increased, the red color reappeared and the solution became cloudy.

Fe3+(aq)+SCN−(aq)____FeSCN2+(aq)