Applications of Le Châtelier's Principle
(September 11 - 15, 2014)
**The purpose of this experiment was to visually observe the effects of how changing certain aspects of the reaction affected the observed equilibrium.
Procedure:
Introductory activity
Part A: Effect of Concentration:
Two different temperature water baths were created, one at 65-70oC, the other ice, and set aside for Part B.
20 mL of potassium thiocyanate solution were poured into a petri dish. The initial color and all subsequent observations were recorded in the data table.
Three drops of iron (III) nitrate were added to different spots in the petri dish, and the resulting solution was swirled until the color was consistent.
Approximately ý pea-sized sample of potassium thiocyanate crystals was added to one spot. After 30 seconds, the solution was mixed.
Approximately a ý pea-sized sample of potassium nitrate crystals was added to one spot in the petri dish. After 30 seconds, this solution was again mixed.
English: 30% hydrochloric acid
English: ions in solution of hydrochloric acid Fra...
Eight cavity test tube mold courtesy of Lake Charl...About a ü pea-sized sample of sodium phosphate monobasic crystals were added to one spot in the petri dish. After 60 seconds, this solution was mixed.
One drop of iron (III) nitrate solution was added to the side of the petri dish, while a pea-sized amount of potassium thiocyanate crystals was added to a different spot. After 30 seconds, the solution was swirled to ensure the crystals fully dissolved and this final solution was saved for use in Part B.
Part B: Effect of Temperature:
The solution saved from Part A was divided evenly into two test tubes labelled 'A' and 'B'. Test tube A was kept as the control. Test tube B was placed into an ice water bath for three to five minutes and then compared to the control.
Test tube B was then placed into a hot water bath for...