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Equilibrium In Organic Liquids


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Equilibrium In Organic Liquids

  1. 1. Physical Principles II CEBU CITY Chemical Engineering Department Name: Juphil Lamanilao Date: October 15, 2009 Course & Yr: BSChE-4 I.TITLE: Equilibrium in Organic Liquids II.OBJECTIVE: • To determine the equilibrium constant of each mixture. III.APPARATUS: Base burette, 5-ml pipette, 1-ml pipette, 7 test tubes with cork, 0.5N NaOH, phenolphthalein, CH3COOC2H5, conc. HCl, glacial CH3COOH, absolute C2H5OH IV.SKETCH: Equilibrium in Organic Liquids 1
  2. 2. Physical Principles II V.TABULATED DATA & RESULTS: Test tube Components Wt. of empty tube Wt. of tube with solution Wt. of Solution Volume of NaOH used Kc 1 5ml 3N HCl + 5ml H2O 17.24 27.61 10.37 43.1 7.77x10-3 2 5ml 3N HCl+ 5ml EtOAc 17.51 27.15 9.64 101.5 0.0192 3 5ml 3N HCl + 5ml EtOAc 17.51 27.39 9.86 113 6.81x10-4 4 5ml 3N HCl + 2ml EtOAc + 1ml EtOH 20.01 29.95 9.97 82.6 4.78x10-4 5 5ml 3N HCl + 4ml EtOAc + 1ml EtOH 17.47 27.09 9.62 97.9 5.48x10-3 6 5ml 3N HCl + 4ml EtOAc + 1ml glacial 17.31 27.20 9.89 142.9 9.96x10-4 7 5ml 3N HCl + 4ml EtOH+ 1ml glacial 17.65 25.09 7.44 44.1 7.91x10-3 VI.SAMPLE COMPUTATIONS: @ 25о C HCl= 1.7899 g/ml CNaOH= (0.5M)(100ml)/ 43.1 ml = 1.16 M CH3COOH= 1.0498 g/ml CH2O= 4.48g÷18g/mol x 51000L = 49.78 M EtOAc= 0.897 g/ml CHCl= 3M mHCl= 1.1789 g/ml (5ml) = 5.89 g Kc= CNaOH/ (CHCl x CH2O) = 7.77x10-3 /M mH2O= (10.39- 5.89) = 4.48 g VII.DATA ANALYSIS: From the exact molarity of both the 3 M HCl and the 0.5 NaOH and the titration volume, the equilibrium amounts of the four substances in the equilibrium mixture can be determined, and the equilibrium constant evaluated. Experimental values gathered for the equilibrium constant in each organic liquids are comparably far since each Equilibrium in Organic Liquids 2
  3. 3. Physical Principles II mixture has varying components. Furthermore, organic compounds are covalently bonded which indicates that their rates of reaction are quite slow. It is much slower than the usual hydrolysis and esterification processes. Each mixture contain little amount of HCl to aid the reaction. HCl and ethyl acetate has the highest Kc while HCl, ethyl acetate and water has the smallest Kc value. The larger the Kc value, the more spontaneous the reaction may become. So, HCl and ethyl acetate gives the most spontaneous reaction since its Kc value is the largest while HCl, ethyl acetate and water yields the opposite value. VIII.APPLICATION TO ChE: Knowledge of equilibrium constant for a given reaction is very helpful aid in laboratory analysis as well as in industry. From a practical standpoint, if you are in a business of producing a given chemical product, it would be essential to know the "K" of a reaction so that you could optimize the yield of the product. Whereas, in laboratory analysis, it is used to predict the direction of the reaction and the extent to which a reaction occurs. IX.CONCLUSION: The equilibrium system is ethanol-acetic acid-ethyl acetate-water. The equation for this equilibrium is: C2H5OH + CH3COOH <-----> CH3COOC2H5 + H2O Equilibrium is established very slowly at room temperature when these four substances are mixed. The rate of reactions (both forward and reverse) can be accelerated by using a catalyst so that the equilibrium can be more rapidly established. 3N HCl is used in this experiment as a catalyst. The mixtures are allowed to stand at room temperature, then aliquots of each mixture are titrated with a standard NaOH solution. The amount of HCl in these mixtures is unchanged since the HCl is only a catalyst. The amount of NaOH required in each titration is equivalent to the amount of HCl and the acetic acid acid in the equilibrium mixture. The amount of acetic acid at equilibrium can be calculated easily from the amount of NaOH used in the titration. The amount of acetic acid found is used to calcuate the amounts of the remaining three substances. The equilibrium constant is then calculated by the equation: Kc = [ethyl acetate] [water] / [ethanol] [acetic acid] The four quantities in the above equation may be replaced by the number of moles of the four substances involved since the volume is constant in each mixture. Equilibrium in Organic Liquids 3