Le Chatelier’s Principle Laboratory Essay Sample

Experiment intent: ? To find the consequence of a alteration on a system at equilibrium and to correlate the ascertained responses with Le Chatelier’s rule. Experiment Chemical list:
Student Provided
1 Tap H2O
1 Toothpicks
1 Distilled H2O
1 Crushed ice
2 Coffee spoons
1 Rubber sets

2 Beaker. 50 milliliter. plastic
1 Magnifier. double
1 Pencil. taging
1 Thermometer-in-cardboard-tube
1 Well-Plate-24
In the Experiment Bag: LeChatelier’s Principle
1 E. D. T. A. . . 15 M ( Na2EDTA ) – 2 milliliter in. Pipet
1 Hydrochloric Acid. 6 M – 2 milliliter in Pipet
1 Magnesium Chloride. 2 M – 3 milliliter in Pipet
1 Phenolphthalein Solution. 1 % – 0. 5 milliliter in Pipet

2 Pipet. Empty Short Stem
1 Sodium Bisulfate Crystals – 0. 5 g in Vial
1 Sodium Bisulfate. 0. 1 M – 4 milliliter in Pipet
1 Sodium Hydroxide. 1 M – 2 milliliter in Pipet
1 Sodium Sulfate. 1 M – 2 milliliter in Pipet
1 Thymol Blue Indicator. 0. 04 % – 0. 5 milliliter in Pipet

Experiment process:
Part I:
1. Fix an ice H2O bath by partly make fulling one of the 50-mL beakers from your LabPaq with tap H2O and crushed ice. Set aside.
2. Fix a hot H2O bath by partly make fulling the 2nd 50-mL beakers from your LabPaq with really hot pat H2O. Set aside.
3. Using a 24-well home base add 5 beads of 2. 0 M MgCl2. Mg chloride
solution to wells C1 and C2. Add 10 beads to Wellss C3 and C4.
4. Add 1 bead of phenolphthalein to wells C1. C2. C3 and C4. Stir with a clean toothpick. Precipitation noted. 5. Add 5 beads of 1. 0 M NaOH. Na hydroxide solution to wells C1. C2. C3. and C4. Stir: solution thickens. turns dark pink. residue besides formed in the solution. 6. Add 1 bead of 6. 0 M HCl. hydrochloric acerb solution to good C1. Stir and enter your observations. Continue to add HCl drop-by-drop to well C1 until you see a colour alteration. Tap solution turns to milky solution once more

7. Add 1 bead of 0. 15 M Na2EDTA to well C2. Stir and enter your observations. Continue to add Na2EDTA drop-by-drop to well C2 until you see a colour alteration. Color alterations to unclutter.
8. Use the marker pencil to label an empty pipet “C3. ” Then. squash the pipet’s bulb. topographic point it in good C3’s solution. and easy let go of the bulb to carefully suck up all the mixture from the well into the bulb.

9. You need to put the pipet bulb from Step 8 into the hot H2O bath. but it will be given to drift. To avoid this. firmly attach the pipet root to a spoon grip with a gum elastic set. Then place the pipet bulb in the H2O bath with the spoon handle outside of the beaker so every bit to non blockade your observations. Cloudy pink solution observed. 10. Repeat Steps 8 and 9 with a 2nd pipet filled with the mixture from good C4. Place © Hands-On Labs. Inc. LabPaq CK-2 68

this pipet into the cold H2O bath. Still fuschia pink colour 11. As the temperature of the mixtures in the pipets alterations. C3- cloudy light pink. C4- fuchsia pink 12. After about 10 proceedingss. exchange the pipets in the baths. ( Put the pipet from the cold H2O bath into the hot H2O bath and frailty versa ) . C3-fuschia pink in the hot H2O bath and C4 – turns to cloudy pink. 13. Dispose of your solutions by pouring them down the drain with running H2O. Rinse your 24-well home base and dry it. Remove the marker pencil Markss from the pipets and rinse them good by sucking up distilled H2O and squashing it out. They will be used in the following portion. so dry the pipets every bit good as possible by squashing their bulbs repeatedly and tapping the tips on a difficult surface covered with a paper towel. Questions:

In Part I the reaction you observed was Mg ( OH ) 2 ( s ) ? Mg2+ ( aq ) + 2 OH- ( aq ) . Compare the colourss you observed in the experiment and reply these inquiries: A. Which manner should the equilibrium displacement when HCl is added? How make your consequences back up your reply? The violet solution changed to milky switching to the right because of the chloride ion. B. Which manner should the equilibrium displacement when Na2EDTA is added? How make your consequences back up your reply? Color alterations rom pink to unclutter. The equilibrium composing of a reaction was altered because there was a alteration in concentration. It should switch to the right because adding the Na2EDTA lowers the concentration of the chloride ion. C. Is this reaction endothermic or exothermic? How do you cognize? The reaction from inquiry ( B ) is a displacement to the right. more merchandises are formed doing it endo thermal. It is devouring energy. Heat is required and heat is a reactant.

Part II:

Again prepare hot and cold H2O baths as instructed in Part I. Stairss 1 and 2. Note: the reactions in Part II are much more elusive than those in Part I. You may hold to wait 30 seconds or longer and look really carefully to detect the reaction and alterations taking topographic point! Use your magnifier to better see the alterations.

1. Using a 24-well home base. add 5 beads of NaHSO4 Na bisulfate solution to wells A1. A2. and A3. Add 10 beads to Wellss A4 and A5.
2. Add one bead of thymol bluish index to each well. Stir with a clean toothpick and Solution turns vino.
3. Add one bead of Na2SO4 Na sulphate solution to well A1 and splash with a clean toothpick. Compare the colour of good A1 with that of good A2. Well A1 has an orange colour compared to good A2 that is wine ruddy. 4. Repeat Step 3. drop-by-drop. until you see a colour alteration. 5. Add a few crystals of solid NaHSO4 to well A3. Stir with a clean toothpick. wait a piece. and enter your observations. Compare the colour of good A3 with that of good A2. Well A3 is purple compared to A2 that is wine ruddy

6. Repeat Step 5 until you see a colour alteration. Precipitation occurs. the purple solution becomes cloudy. © Hands-on Labs. Inc. LabPaq CK-2 69
7. Use the marker pencil to label an empty pipet “A4. ” Then squeeze the pipet bulb. topographic point it in good A4’s solution. and easy let go of the bulb to carefully suck up all the mixture into the bulb. 8. You need to put the pipet bulb from Step 7 into the hot H2O bath. but it will be given to drift. To avoid this firmly attach the pipet root to a spoon grip with a gum elastic set. Then place the pipet bulb in the H2O bath. with the spoon handle outside of the beaker so every bit to non blockade your observations.

9. Make certain the H2O bath is every bit hot as possible. If the H2O bath is non really hot the expected colour alteration may be hard to see. Put the pipet bulb from measure 8 into the hot H2O bath. Record the beginning temperature of the hot H2O bath. Temperature: 97 grades Celsius 10. Repeat Steps 7 and 8 with a 2nd pipet for the mixture from good A5. Topographic point this pipet into the cold H2O bath.

11. Record the beginning temperature of the cold H2O bath. Beginning temperature ; 100 grades Celsius. 12. When you observe alterations in the mixtures in the pipets enter your observations and the H2O bath temperatures. Solution turns light pink

13. Compare the concluding solutions to that in good A2 Pipet A4 is light pink compared to Pipet A5 that is light vino ruddy. 14. After about 10 proceedingss exchange the pipets in the baths. ( Put the pipet from the cold H2O bath into the hot H2O bath and frailty versa. ) Switch overing pipet A4 to cold H2O bath turns solution darker fuchsia pink colour and pipet A5 to hot H2O bath turns solution even more lighter vino ruddy colour. 15. Dispose of your solutions by pouring them down the drain with running H2O. Rinse and exhaustively dry your 24-well home base. Rinse your pipets exhaustively with distilled H2O. Dry the pipets every bit good as possible by squashing their bulbs repeatedly and tapping the tips on a difficult surface covered with a paper towel.

Questions Part II:
In Part II the reaction you observed was HSO4- ( aq ) + H2O ( cubic decimeter ) ? H3O+ ( aq ) +SO42- . Compare the colourss you observed in the experiment and reply these inquiries: A. Which manner should the equilibrium displacement when Na2SO4 is added? How make your consequences back up your reply?

Few beads of crystal bends violet and cloudy and the equilibrium displacement to the left. B. Which manner should the equilibrium displacement when NaHSO4 is added? How make your consequences back up your reply? The solution turns violet and the equilbrum displacement to the left. It produces heat and energy is released. C. Is this reaction endothermic or exothermic? How do you cognize? This reaction is exothermal because of the precipitation. the solution undergoes a alteration in concentration. volume so equilibrium will switch to the counter the alteration and set up a new equilbrum.