Date conducted: 2/9/2012
Experiment purpose: To determine the effect of a change on a system at equilibrium and to correlate the observed responses with Le Chatelier’s principle.
Experiment Chemical list:
Student Provided 1 Tap water
1 Distilled water
1 Crushed ice
2 Coffee spoons
1 Rubber bands 2 Beaker, 50 mL, plastic
1 Magnifier, dual
1 Pencil, marking
In the Experiment Bag: LeChatelier’s Principle
1 E.D.T.A., .15 M (Na2EDTA) - 2 mL in, Pipet
1 Hydrochloric Acid, 6 M - 2 mL in Pipet
1 Magnesium Chloride, 2 M - 3 mL in Pipet
1 Phenolphthalein Solution, 1% - 0.5 mL in Pipet
2 Pipet, Empty Short Stem
1 Sodium Bisulfate Crystals - 0.5 g in Vial
1 Sodium Bisulfate, 0.1 M - 4 mL in Pipet
1 Sodium Hydroxide, 1 M - 2 mL in Pipet
1 Sodium Sulfate, 1 M - 2 mL in Pipet
1 Thymol Blue Indicator, 0.04% - 0.5 mL in Pipet
Experiment procedure: Part I:
1. Prepare an ice water bath by partially filling one of the 50-mL beakers from your
LabPaq with tap water and crushed ice. Set aside.
2. Prepare a hot water bath by partially filling the second 50-mL beakers from your
LabPaq with very hot tap water. Set aside.
3. Using a 24-well plate add 5 drops of 2.0 M MgCl2, magnesium chloride solution to wells C1 and C2. Add 10 drops to wells C3 and C4.
4. Add 1 drop of phenolphthalein to wells C1, C2, C3 and C4. Stir with a clean toothpick. Precipitation noted.
5. Add 5 drops of 1.0 M NaOH, sodium hydroxide solution to wells C1, C2, C3, and C4.
Stir : solution thickens, turns dark pink.residue also formed in the solution.
6. Add 1 drop of 6.0 M HCl, hydrochloric acid solution to well C1. Stir and record your observations. Continue to add HCl drop-by-drop to well C1 until you see a color change. Pink solution turns to milky solution again
7. Add 1 drop of 0.15 M Na2EDTA to well C2. Stir and record your observations.
Continue to add Na2EDTA