Determination of the Equilibrium Constant

CHECHE NortheasternUniversity,Boston
23 5+62323222222222222
  
  
  Determination of the Equilibrium Constant for the Reaction of Acetic Acid with Isopropanol
  
1.  
Measure 14.2 mL (d = 1.049 g/mL) of glacial acetic acid into a clean 250 mL Erlenmeyer flask and carefully add 19.2 mL (d = 0.785 g/mL) of isopropanol. Stir the mixture for about one minute. (Use a micropipette to deliver 0.2mL i.e. 200uL)
  
2.  
Pipet three 1.00 mL samples of this solution into clean Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution to each aliquot.
  
3.  
Titrate each solution using 0.200 M NaOH until the pale pink endpoint is reached. The results of these titrations allow you to calculate the initial concentration of acetic acid in the solution. Record the data in your laboratory notebook.
  
4.  
To the remaining mixture in the 250 mL flask, add 1.00 mL of concentrated sulfuric acid solution and carefully stopper the flask to prevent evaporation of the mixture.
  This flask will be stored until the next lab period.
  
5.  
Prepare a solution of sulfuric acid by adding 1.00 mL of the concentrated sulfuric acid solution to 30.5 mL of distilled
water. Stir the mixture well.
  
6.  
Pipet three 1.0 mL samples of the sulfuric acid solution from step 5 into clean Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution to each aliquot.
  
7.  
Titrate each solution using 0.200 M NaOH until the pale pink endpoint is reached. The results of these titrations allow you to calculate the concentration of sulfuric acid in the solution. Record the data in your laboratory notebook.
  
  Go on to the next section of the experiment on the reaction between isopropyl acetate and water (step 11).  Next lab period you will continue your measurement of the equilibrium constant here.
  
NEXT
LABORATORY MEETING
  
8.  
Pipet three 1.00 mL samples of the aged reaction
mixture into Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution.
  
9.  
Titrate each solution with 0.200 M NaOH until the pale pink endpoint is reached.
  
10.
Use the results to determine the amount of acetic acid remaining in the solution after the two week reaction time.
  
  
  Determination of the Equilibrium Constant for the Reaction of Isopropyl acetate with Water
  
11.
Measure 29.2 mL (d= 0.874 g/mL) of isopropyl
acetate into a clean 250 mL Erlenmeyer flask and carefully add 4.5 mL (d = 1.00 g/mL) distilled water. Stir the mixture for about one minute. Again use the micropipette to deliver 0.2mL i.e. 200uL of isopropyl acetate.
  
12.
Calculate the initial concentrations of isopropyl acetate and water in this mixture. Record the data in your laboratory notebook.
  
  13. Pipette 1.00 mL of concentrated
sulfuric acid into the solution from Step 11 and carefully stopper the flask to prevent evaporation of the mixture.   This flask will also be stored until next lab period.
  
14.
Prepare a solution of sulfuric acid by adding 1.00 mL of the concentrated sulfuric acid solution to 33.7 mL of distilled
water. Stir the mixture well. Use the micropipette to deliver 0.7mL, i.e. 700uL of distilled water.
  
15.
Pipet three 1.00 mL samples of the sulfuric acid solution from step 14 into clean Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution to
each aliquot.
  
16.
Titrate each solution using 0.200 M NaOH until the pale pink endpoint is reached. The results of these titrations allow you to
calculate the initial concentration of sulfuric acid in the solution. Record the data in your laboratory notebook.
  
  
Go on to the next section of the experiment on the reaction between acetic acid and an unknown alcohol (step 20). Next lab period, you will continue your measurement of the equilibrium constant here.
  
NEXT LABORATORY MEETING
  
17.
Pipet three 1.0 mL samples of the aged reaction mixture into Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution.
  
18.
Titrate each solution with 0.200 M NaOH until the pale pink endpoint is reached.
  
19.
Use the results to determine the amount of acetic acid in the solution after the two week reaction time.
  
  
  
  
  
  
  Determination of the Equilibrium Constant for the Reaction of Acetic Acid with an UnknownAlcohol
  
20.
Obtain a sample of a different alcohol from
your instructor. Using its density, determine how much of this alcohol is needed to prepare an equimolar (1:1) mixture with 14.2 mL of acetic acid.
  
21.
Measure 14.2 mL (d = 1.049 g/mL) of glacial acetic acid into a clean 250 mL Erlenmeyer flask and carefully add the appropriate volume of your alcohol. Stir the mixture for about one minute.
  
22.
Pipet three 1.00 mL samples of this solution into clean Erlenmeyer flasks containing 25 mL of distilled water each. Add 3 drops of phenolphthalein solution to each aliquot.
  
23.
Titrate each solution using 0.200 M NaOH until the pale pink endpoint is reached. The results of these titrations allow you to calculate the initial concentration of acetic acid in the solution. Record the data in your laboratory notebook.
  
24.
To the remaining mixture in the 250 mL flask, add 1.00 mL of concentrated sulfuric acid solution and carefully stopper the flask to prevent evaporation of the mixture.
  This flask will be stored until next lab period.
  
25.
Calculate the total volume of solution left in the 250 mL flask. It should be the sum of the volumes of acetic
acid and alcohol less than 3.0mL.
  
26.
Prepare
a solution of sulfuric acid by adding 1.00 mL concentrated sulfuric acid to the amount of distilled water calculated in step 25. Stir the mixture well.
  
27.
Pipet three 1.0 mL samples of the sulfuric acid solution from step 26, into clean Erlenmeyer flasks containing 25 mL of distilled water each. Add 3 drops of phenolphthalein solution to each aliquot.
  
28.
Titrate each solution using 0.200 M NaOH until the pale pink endpoint is reached. The results of these titrations allow you to calculate the initial concentration of sulfuric acid in the solution. Record the data in your laboratory notebook.
  
  
  
You may stop here for this week. Next week, you will continue your measurement of the equilibrium constant here.
  
NEXT LABORATORY MEETING
  
29.
Pipet three 1.0 mL samples of the aged
reaction mixture into Erlenmeyer flasks containing 25 mL of distilled water. Add 3 drops of phenolphthalein solution.
  
30.
Titrate each solution with 0.200 M NaOH until the pale pink endpoint is reached.
  
31.
Use the results to determine the amount of acetic acid remaining in the solution after the two week reaction time
  
[寄僥6定雫] 忖方5387 誘後晩豚2015-7-12 9:59:00
---- By ROOT 2015-7-12 21:19:25