• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Finding the Equilibrium Constant for the Ester Formation of Ethyl ethanoate

Extracts from this document...


Finding the Equilibrium Constant for the Ester Formation of Ethyl ethanoate Michael Zuber Introduction: In this experiment 6 different mixtures of known amount of acid, alcohol and/or ester were mixed with dilute hydrochloric acid in a stoppered bottle. The mixture is then set aside for a week to reach equilibrium at room temperature. The mixture is then titrated against a solution of 1 mol.dm-3 NaOH to determine the total amount of acid present in the equilibrium. From this the amount of ethanoic acid can be found and therefore the amount of the other reagents can be found. These values can then be used to find the equilibrium constant for the reaction. The equation for the reaction is: Raw Data: Below is a table of the different volumes of the chemicals initially added in each solution: Solution HCl (cm3) Water (cm3) Ethyl ethanoate (cm3) Ethanoic acid (cm3) Ethanol (cm3) 1 5 0 5 0 0 2 5 1 4 0 0 3 5 3 2 0 0 4 5 0 4 1 0 5 5 0 0 1 4 6 5 0 0 2 3 Below is a table of the volume of NaOH needed to neutralize the different solutions at equilibrium: Solution NaOH (cm3) used to neutralise soltuion (1) NaOH (cm3) used to neutralize soltuion (2) NaOH (cm3) used to neutralise soltuion (3) 1 44.2 43.7 42.9 2 44.5 45.2 3 32.4 32.1 31.1 4 52.9 50.9 51.8 5 22.8 23 6 37.5 36.4 From these values we can find an average amount of 1 mol.dm-3 NaOH needed to neutralize each solution can be found. ...read more.


If this is taken away from the mass of the HCl(aq) than the mass of water can be found. Mass of water = 5.28 - 0.5475 = 4.73g Converting this to moles: Moles water = 4.73/18 = 0.263 moles Since water has a density of 1 g.cm-3 the amount of cm3 of water added to the initial mixture equals the mass of water added to the initial mixture. Therefore this value must be added to the mass of water and a new mole value will be found. The amount of moles of water added to each solution initially is shown in the below table. Solution Initial Moles water 1 0.263 2 0.318 3 0.429 4 0.263 5 0.263 6 0.263 To find the moles of ethyl ethanoate, a similar approach must be used. In the solution where no ethy; ethanoate was introduced initially, the amount of moles of ethyl ethanoate produced will equal to the amount of moles of ethanoic acid reacted (due to the 1 : 1 mole ratio of the reaction equation). However, for the solutions where ethyl ethanoate was put into the mixture the amount of moles of ethyl ethanoate will equal the amount of moles initially put in subtracted by the amount of moles of ethanoic acid. The mass of 5cm3 ethyl ethanoate was measured out to be 4..37g. Therefore for 5cm3 of ethyl ethanoate there is 4.37/88 = 0.0497 moles. For 4 cm3 the amount of moles will equal 4/5 x 0.0497 = 0.0397 For 2 cm3: moles = 0.0199 These values are then subtracted by the moles of ethanoic acid in their respective solutions. ...read more.


Labeling of Liquids: An error in this practical was that not all of the liquids were properly labeled. Students were told where each liquid was in the room but not all of the prepared biurettes were properly labeled with the liquids inside of them students could have easily gotten confused. For example, since both the distilled water and the aqueous hydrochloric acid have the same colorless appearance, a student could easily get confused between the two and mix them up therefore leading to inaccurate mixtures therefore affecting our results. Improvements: Accuracy of Apparatus: As explained above, the use of the biurettes is a fairly accurate method of measuring out the liquids. However, more accurate apparatus could be used. For example, electronic flow meters would give even more accurate results. Time Management: In order to allow students to get there own sets of results more time should have been allotted to this experiment so that each individual student could get there own results. Sharing of Data: The sharing of data is very useful to get a wider range of values. However, when there is a very limited amount of results it can be more problematic than helpful. Therefore, if the above proposal is used data could still be shared because if one set of results was wrong it would have less of an effect on the overall results and it would stick out more. Labelling of Liquids: In order to avoid confusion, all biurettes should have been properly labeled with the liquids that they contained. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Chemistry essays

  1. Aim: Using an iodine clock reaction to find the order of hydrogen peroxide and ...

    The full extent of the errors are evaluated in the evaluation section of this lab report. Calculating Rate Rate can be determined used the equation where time is substituted by the tame taken for the reaction to happen in each experiment.

  2. Acids/Bases Design Lab. How does a change in the pH value of a solution ...

    Qualitative observations were recorded. 10. Another clean, dry, and empty 50cm3 beaker, labeled 'Beaker ART1' was massed out on the electronic milligram balance. Its mass was recorded to the nearest 0.001g. 11. After exactly 1 minute has elapsed, the 50cm3 beaker labeled AT1 was decanted of its hydrochloric acid solution, making sure that the zinc metal strip remained.

  1. Faraday's Constant

    Be careful to avoid any movement of the electrodes during the electrolysis. 3) Thorough washing and drying of the electrodes is vital. A tiny amount of moisture left on the electrodes causes a considerable error in the mass calculations. 4)

  2. Chemistry extended essay - investigate the effect of 2-bromo-2-methyl propane concentration and temperature of ...

    Evaluating the mechanism: The only reactant that is undergoing change in the rate determining step is t-butyl chloride and so such reactions is a unimolecular and follow a first order equation (Sn1, E1). "This means that the rate of the reaction varies directly with the concentration of t- butyl chloride".

  1. Esterification Equilibrium

    Qualitative Data Qualitative Data Takes around 1 week for the mixture to reach equilibrium Placed base (NaOH) in burette and acid (HCl) in the beaker with the indicator (Phenolphthalein) Colour change when certain amount of base was titrated into the beaker (reached equilibrium)

  2. Group 4

    The maximum of the Maxwell-Boltzmann distribution shows the intermediate speed at which the largest number of molecules are traveling. As the temperature increases, the number of molecules that are traveling at high speeds increases, and the speeds become more evenly distributed in the curves.

  1. Measuring the fatty acid percentage of the reused sunflower oil after numerous times of ...

    mε = 5.433 ± 0.018% g A% = (71.5 ± 0.1% x 0.0028 x 100) 5.433 ± 0.018% = 3.7% ± 0.1% ml/g oleic acid Trial 2: V = 67.0 ± 0.1 ml → Vε = 67.0 ± 0.1% ml m = 5.249 ± 0.001 g → mε = 5.249

  2. To determine the standard enthalpy of formation of Magnesium Oxide using Hess Law.

    and ?HY (Trial 2) was taken. * ?HY = -106.3kJ.mol-1 Therefore, the standard enthalpy of reaction of reaction 2: MgO (s) + 2HCl (aq.) ? MgCl2 (aq.) + H2O (l) ------------ ?HX = -106.3kJ.mol-1 Calculating ?HMgO Since the enthalpies of reaction for both reaction 1 and reaction 2 are known, Hess? law can be applied and

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work