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

alkali titration

Extracts from this document...

Introduction

Data Collection Table 1. Data collected from the experiment. Table shows three separate trials from the experiment and the Final burette reading, Initial burette reading and Volume delivered from each trial. The average of accurate titration volumes is also included in the table. Titration Rough * Trial 1 Trial 2 Trial 3 Final burette reading (cm3) �0.075 21.0 20.6 20.4 40.7 Initial burette reading (cm3) �0.075 0.0 0.0 0.0 20.4 Volume delivered (cm3) �0.15 21.0 20.6 20.4 20.3 Average of accurate titration volumes : (dm3) �0.15 20.4 * The Rough was excluded during the calculation of the mean as the rough was a trial to indicate the general whereabouts of the end point, which is inaccurate of the exact end point. Table 2. Observations collected during the experiment. Table contains observations which were recorded during each trial of the experiment. Trials Observations Before trials * When water was added to the crystals of oxalic acid, it dissolved almost instantly with a light stirring of the beaker. Rough * When two drops phenolphthalein was added to the solution of sodium hydroxide, the solution turned pink. * After adding about 20.8dm3 of oxalic acid into the sodium hydroxide solution, while swirling the conical flask, the solution turned completely clear - the oxalic acid was filled up to 21dm3 to have a rounded rough end point to work with. ...read more.

Middle

The result was 0.00194 moles of NaOH in the sodium hydroxide solution with an uncertainty of �1.23%. The amount of oxalic acid presented in the average volume required to react exactly with the sodium hydroxide solution was also calculated; by dividing the moles of NaOH (0.00194�1.23%) by 2, based on the 1:2 reaction ratio stated before. The result was 0.00097 moles with an uncertainty of �1.23%. The amount of oxalic acid present in 250cm3 was also calculated. The concentration of acid in 250mL is the same as the concentration of acid in 1L, therefore, the concentration of acid in 1dm-3 of the oxalic acid solution is the same concentration as the acid in 250mL. With this understood, the equation c = n/v was used once again. The 'concentration' was first calculated by dividing the moles of NaOH by 0.25dm3. The result (0.05mols dm-3 �2.09), was used in further calculations to determine the moles of oxalic acid by multiplying the previous calculated concentration (0.05mols dm-3 �2.09) with 0.25dm3, resulting in the moles of oxalic acid in the 250mL solution as 0.0125mols �2.15%. This value was used in the calculation of the mass of one mole of oxalic acid. The equation n = m/MM was used in this calculation. The MM (molar mass) was first calculated, dividing the mass of oxalic acid crystals by the moles of oxalic acid (1.5 / 0.0125). ...read more.

Conclusion

This could be prevented by either slowly removing the funnel or using the funnel up to a certain mark, remove it and fill up to the desired amount with the use of a small pipette - drop by drop. When using the 20mL pipette to transfer the sodium hydroxide into the conical flask, the tip of the nozzle had a drop that was tempted to drop out of the pipette. Avoid touching the sides and move the pipette over the flask slowly would reduce the chances of it dripping out and altering the volume of solution. A small amount of the solution was also stuck at the tip of the nozzle after being emptied. By touching the tip to the side of the flask would help that tiny bit of solution flow out. If possible have the nozzle flat on the side of the flask, this would allow it to flow out smoothly. To avoid or reduce these significant errors, these solutions and improvements should be taken into consideration during future repetition of this experiment. The experiment overall was invalid. Though the values in data collection may have been to a 0.10cm3 difference, the final calculation of the percentage error, 16.87%�1.74%, was much greater than the desired 1% causing the experiment to be invalid. ?? ?? ?? ?? 6 ...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. Preparation of a standard solution of oxalic acid and using it to standardize a ...

    This would cause an imbalance in the solution and more acid would be required to neutralize the solution. The percentage error lies outside the uncertainties of the experiment. This means that the results obtained were not very accurate and are therefore not reliable.

  2. pKa. When constant successive portions of Sodium Hydroxide are added to Acetic Acid; how ...

    A smaller Ka value suggests a larger pKa value. The larger the pKa value the weaker the acid. Base solution is added until the equivalence point is reached. Thus, to determine the pKa of Acetic acid, the amounts of base mixed with acid will vary, the pH will be measured

  1. Enthalpy Change Design Lab (6/6)How does changing the initial temperature (19C, 25C, 35C, and ...

    and 1.00 mol dm-3 KOH(aq). Control Variables 1. The state of reactants must be kept constant throughout the course of the investigation. This is because of the fact that at different physical states, substances have different enthalpies because of the nature of the bonds that hold them together.

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

    Many cell types can use either glucose or fatty acids for this purpose. In particular, heart and skeletal muscle prefer fatty acids. Although this information can lead to a thought that an increase in fatty acids may be beneficial for human body, during the process of lipolysis which is the

  1. To determine the molecular mass of an unknown alkali metal carbonate, X2CO3.

    Uncertainty for the value of average volume of HCl required for complete neutralization is ±0.10cm3 since averaging values do not lead to change in uncertainties.

  2. The use of volumetric flask, burette and pipette in determining the concentration of NaOH ...

    The OH? ions in the NaOH solution react with the H3O+ ions in the HNO3 solution and it shows as below: 1. H3O+(aq) + OH?(aq) H2O(l) As long as excess H3O+ ions in the solution, staying acidic, the phenolphthalein stays mostly in the acid form, and the solution is colorless.

  1. The purpose of this experiment is to determine the concentration of a solution of ...

    The drop is a constituent of the solution and contains moles of the solution which gets left behind. This error in experimental procedure will lead to less volume being used hence increasing the concentration and leading to an error in the titration procedure.an improvement for this error is to clean

  2. Chemistry Titration Acid Base Lab

    The least amount of sodium hydroxide required to reach the endpoint of the reaction for the indicators used are displayed as followed: methyl orange, bromocresol green, phenolphthalein, bromothymol blue and methyl red. Many indicators were used to determine which one was right for this specific lab.

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