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

Pka of ethanoic acid

Extracts from this document...

Introduction

Determining the pka value of ethanoic acid A titration is a procedure that can be used in analytical chemistry to determine certain value or concentration of a substance. The aim of this experiment is to determine the pka value of ethanoic acid. Every acid has its own specific dissociation constant, ka, which measures the strength of the acid. pka is equal to the negative logarithm of ka .In order to determine the pka constant for ethanoic acid it was titrated with NaOH. The reaction is as below CH3COOH + NaOH (aq) � CH3COO- + Na+ + H2O ka = [CH3COO-][H+] [CH3COOH ] pka = - log ka Materials: - NaOH (0.1 mol dm-3), CH3COOH (0.1 mol dm-3), pH meter, stand, clamp, thermometer, beakers, pipette, magnetic spin, titration pipette. Methods:- 1. 25 ml of ethanoic acid was poured into a beaker and placed below the titration pipette. ...read more.

Middle

The pH value also took an abrupt increase from 5.89�0.01 to 11.31�0.01 as the volume of NaOH increased from 15�0.05 to 16�0.05 ml. Graph 1. Change in the pH value of Ethanoic acid as the volume of NaOH increases As seen from Graph 1 the pH value gradually increases up to a point where it drastically show increase in the pH value. Then it begins to increase gradually again. All of this is due to the change of ethanoic acid to its conjugate base as more and more sodium hydroxide is added. The pka value of ethanoic acid can be found by analyzing the above titration graph. From the graph it is possible to find the equivalence point. The equivalence point is a point where the acid-base solution is neutral. This means that all of the acid has been consumed and will have a pH value greater than 7 since ethanoic acid is a weak acid and NaOH is strong acid. ...read more.

Conclusion

Dividing this value by two will result in 7.75�0.32 ml. (The new uncertainty was found by calculating the percentage uncertainty of 15.5). The pH value at 7.75�0.32 ml is 4.60�0.01. The literature pka value of ethanoic acid is found to be 4.76. Therefore the experimental value calculated here is very close. The difference may be due to uncertainties and limitations of the experiment. Conclusion: - according to this experiment the pka value of ethanoic acid was found to be 4.60. This is a very close result to the literature value which is 4.76. The difference may be a result of uncertainties and limitations. Limitations: - the volume used for titration was 25 ml. instead using higher volumes of sodium hydroxide and ethanoic acid would allow the effect of one drop to be more accurate and it will also minimize the random/systematic errors on the final result. Improvements: - using higher volumes such as 100ml of sodium hydroxide and ethanoic acid. ?? ?? ?? ?? ...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. pKa. When constant successive portions of Sodium Hydroxide are added to Acetic Acid; how ...

    So what is changed is the amount of base in the conical flask and it is this amount of base that changes the pKa. Thus, I hypothesize that as the amount of Sodium Hydroxide increases, pH will gradually increase until it reaches the end point where there will be a sudden increase.

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

    Add H2O2, the acid and the water together into one beaker, labeled "Solution B". 5. Pour one solution into a larger, marked beaker marked to indicate it is the beaker where the reaction takes place. 6. Pour the second solution into the larger beaker and start the timer as soon as the second solution hits the first solution.

  1. Research Question By measuring the pH value of the acetic ...

    ] / Molarity of solution pKa = - log10 (Ka) Ethanoic acid is a typical weak acid (CH3COOH) and will be used during this experiment. As temperature and the environmental conditions is a major factor and can immensely affect this experiment, this experiment will be carried out at standard lab conditions.

  2. Espuma a base de cscara de pia

    y Hexa (HDI). A continuaci�n les voy a mostrar las f�rmulas estructurales y los nombres de cada uno6: Tolueno-2,4-diisocianato (TDI) Naftalina-1,5-diisocianato (NDI) O=C=N--- (CH2)6---N=C=O Difenilmetano-4,4-diisocianatos (MDI) Hexa-1,6-diisocianato (HDI) La forma hexagonal que se presenta en el TDI, NDI y

  1. Determining Ka by the half-titration of a weak acid

    was at a volume was at 28cm3 as it has the steepest gradient. Thus, the half-equivalence is at half a volume, 14cm3. At this volume the PH is 4.8 ±0.2 Using this value, as = PKa + = PKa PKa= 4.8 ±0.2 4.8±4.2% = = 10-4.8 ±4.2% Conclusion: I have

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

    The smoke point of oil is the temperature at which the oil begins to decompose and give off visible fumes (smoke). If the oil's smoke point is just above 190 0C (375 0F), which is the normal deep- frying temperature, after frying its smoke point will drop below 190 0C (375 0F)

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