• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19
  20. 20
    20
  21. 21
    21
  22. 22
    22
  23. 23
    23
  24. 24
    24

Deducing the quantity of acid in a solution

Extracts from this document...

Introduction

Sofia Gaggiotti Chemistry coursework: Deducing the quantity of acid in a solution 20/03/2008 Index Aim and Background information 3 Hazards 3 Protection 4 Method 5 Previous calculations 5 Making the Solution 6 Equipment needed 6 Quantities of materials needed 8 Procedure 8 Making the Titration 9 Equipment needed 10 Procedure 13 References 15 Results and calculations 16 Evaluation 19 Chemistry coursework: Deducing the quantity of acid in a solution Aim and background information The aim of this experiment is to find how to develop and determine an accurate, precise and reliable concentration of an acid rain solution. 1 To do this, we are going to make first a solution of sodium carbonate with distilled water and then a titration in order to calculate the concentration of sulphuric acid in a solution. Solution: a solution is a homogeneous mixture composed of two or more substances. In this mixture, a solute is dissolved in a solvent. Solutions are characterized by interactions between the solvent phase and solute molecules or ions that result in a net decrease in free energy. 2 Titration: a titration is a laboratory technique by which we can determine the concentration of an unknown reagent using another reagent that chemically reacts with the unknown. At the equivalence point (or endpoint) the unknown reagent has been reacted with the known reagent. A chemical indicator (for example, a change in the colour of the unknown) will let us know when that point has arrived.3 This symbol equation explains the reaction that we are doing. This shows that the moles of sodium carbonate used are the same number of moles used of acid sulphuric. Na2CO3 (aq) + H2SO4 (l) --> Na2SO4 (aq) + H2O (l) + CO2 (g) Hazards In this experiment, the substances used and their hazards are: * Sulphuric acid Given the concentrations of H2SO4 used (between 0.05-0.15), it can not be labelled as irritant because irritant solutions should be equal to or stronger than 0.5 M and weaker than 1.5 M. ...read more.

Middle

and Otter C. 2004. Revise As Chemistry. Oxford: Heinemann, page 40. "Using concentrations in calculation" in Chemical Ideas .Heinemann, page 13 "Weighing boat" in: http://www.chem.ubc.ca/courseware/154/tutorials/exp1A/weigh/ Definition of "Teflon" in http://www.wordreference.com/definition/teflon "Beaker" in http://en.wikipedia.org/wiki/Beaker_(glassware) "Burette" in http://en.wikipedia.org/wiki/Burette "Filler pipette" in http://www.dynamicaqua.com/pipettes.html "Conical flask" in http://en.wikipedia.org/wiki/Erlenmeyer_flask "Indicator methyl orange" in http://209.85.165.104/search?q=cache:SKkYbrlmWCsJ:antoine.frostburg.edu/chem/senese/101/acidbase/faq/methylorange.shtml+methyl+orange+indicator&hl=en&ct=clnk&cd=4&gl=uk Results and calculations to obtain the concentration of the solution Rough titration 1st titration 3rd titration 4th titration Final volume (cm3) 24.00 20.15 20.25 20.20 Initial volume (cm3) 0.00 0.00 0.00 0.00 Titre (cm3) 24.00 20.15 20.25 20.20 To calculate the final concentration of the acid solution, we first need to know the concentration and mass of Na2CO3. To know the actual concentration of Na2CO3 used in the titration we need to know the actual mass of Na2CO3 added. When weighing the solid, we first weighed the weighing boat, which was 0.90g. Then we added the solid until 3.55g. This means that we weighed exactly 2.65g of Na2CO3 as 3.55 - 0.90 = 2.65g. Knowing that, we can now calculate the actual final concentration of the solution Step 1: Having the right units. First of all we need to change from cm� to dm�, in order to have the wanted units related to the volume of Na2CO3. So, 250 cm3 = 0.25 dm3 Step 2: Calculate the number of moles of the sodium carbonate solution. Knowing that m (mass) = n (number of moles) x Mr, we can then work out the number of moles of sodium carbonate So, we first need to calculate the Mr of sodium carbonate: Mr of Na2CO3 = 23x2 + 12 + 16x3 Mr of Na2CO3 = 106 Therefore, n = m/Mr n = 2.65g/106 n = 0.025 moles of Na2CO3 Step 3: Calculate the concentration of sodium carbonate needed. To do that, we need to use the equation n (number of moles) = C (concentration) x V (volume). Knowing that the number of moles is 0.025 and that the volume used was 0.25dm3, we can then calculate the actual concentration of Na2CO3. ...read more.

Conclusion

It seems more difficult to avoid and/or reduce the consequences of the precision errors taking into account that they do not depend on ourselves but the equipment. However, these errors could be reduced by using other apparatus that have less percentage error. This table compares the consequences of the significance between the procedure and the precision error: Procedure errors Consequences Overall view Precision errors Consequences Overall view Weight - Transferring - Rinsing - Particles of the solid could fall whilst transferring it to the weighting boat. - Particles could be left if not rinsed properly Tend to reduce the amount of the substances Balance �0.005g Can reduce or increase the amount of substances Pipette Reading the meniscus Not reaching the valid endpoint Can give either an earlier or later endpoint Pipette �0.04cm3 Can give either a higher or lower result Volumetric flask Reading the meniscus Not reaching the valid endpoint Can give either an earlier or later reaction Volumetric flask �0.2cm3 Can giver either a higher or lower result Burette Reading the meniscus Not having concordant titres Can give either a higher or a lower result Burette �0.05cm3 Can give either a higher or lower result 1 Cf. Aim in Revised 2005 help sheet 2 Cf. "Solution" in http://en.wikipedia.org/wiki/Solution 3 Cf. "Titration" in http://members.aol.com/profchm/titrate.html 4 Cf. "Sulphuric (VI) acid in Hazcard 98A 5 Cf. "Methyl orange" in http://www.proscitech.com.au/catalogue/msds/c118.pdf and Hazcard 32 6 Cf. "Sodium carbonate" in : http://www.jtbaker.com/msds/englishhtml/s3242.htm and Hazcard 95A 7 Cf. "Concentrations of solutions" in Daniels A., Johnston L. and Otter C. 2004. Revise As Chemistry. Oxford: Heinemann, page 40 8 Cf. "Using concentrations in calculation" in Chemical Ideas .Heinemann, page 13 9 Cf. "Weighing boat" in: http://www.chem.ubc.ca/courseware/154/tutorials/exp1A/weigh/ 10 Cf. "Teflon" in http://www.wordreference.com/definition/teflon 11 Cf. "Beaker" in http://en.wikipedia.org/wiki/Beaker_(glassware) 12 Cf. "Burette" in http://en.wikipedia.org/wiki/Burette 13 Cf. "Filler pipette" in http://www.dynamicaqua.com/pipettes.html 14 Cf. "Conical flask" in http://en.wikipedia.org/wiki/Erlenmeyer_flask 15 Cf. "Indicador methyl orange" in http://209.85.165.104/search?q=cache:SKkYbrlmWCsJ:antoine.frostburg.edu/chem/senese/101/acidbase/faq/methyl-orange.shtml+methyl+orange+indicator&hl=en&ct=clnk&cd=4&gl=uk ?? ?? ?? ?? Chemistry coursework: Sofia Gaggiotti Deducing the quantity of acid in a solution 23 Chemistry coursework: Sofia Gaggiotti Deducing the quantity of acid in a solution 2 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Inorganic Chemistry section.

Found what you're looking for?

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

Here's what a star student thought of this essay

5 star(s)

Response to the question

Exceptional piece of coursework. Aims and background information are very clearly worded, and explains the chemistry theory behind the practical well. I would like to see the use of the experiment in the real world more clearly defined. Main body ...

Read full review

Response to the question

Exceptional piece of coursework. Aims and background information are very clearly worded, and explains the chemistry theory behind the practical well. I would like to see the use of the experiment in the real world more clearly defined. Main body of text, conclusions and evaluation all to a very high level and standard and this candidate is exemplary for the level I would expect for an A level student.

Level of analysis

Use of chemistry equations correct. Clearly defines any hazards in the experiment to a high level and quotes from a range of different sources showing clear research behind the experiment. Calculations included to determine reagents also seem fine. High standard of coursework to be calculating measurements from scratch rather than using set measurements. Very detailed and accurate method, and details of each part of the equipment used and what they are used for, not sure the candidate needs to go into what each piece of equipment is used for, but to this level even a new chemistry a level student would start to understand the procedure taking place in front of them. Their evaluation and results calculations are very detailed, correct and to a very high level of understanding. Calculated most possible errors that could have affected the experiment and suggests possible improvements, although there could have been slight more detail about the improvements suggested.

Quality of writing

Grammar, spelling and punctuation all to a very high standard.


Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by skatealexia 11/03/2012

Read less
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 AS and A Level Inorganic Chemistry essays

  1. Peer reviewed

    Determining the concentration of acid in a given solution

    5 star(s)

    A pipette measuring 25cm3 has a precision uncertainty of �0.06cm3, yet because of the larger volume it measure, it has a percentage error of 0.24%. I am going to use a pipette which measures 25cm3 of solution as I am not limited on the amount of solution I can use

  2. Chem Lab report. Standardization of hydrochloric acid by sodium carbonate solution

    Also, if phenolphthalein was used, the color change of reaction mixture, which was from purple to pink, would be not sharp and so a large error would be made when determining the end-point of the titration. In this experiment, it must be sure that the sodium carbonate solid prepared at

  1. Determination of the purity of Sodium Carbonate

    Concentration of hydrochloric acid = 0.04 x 2 = 0.08 mol dm-3 To make up a solution of 250cm3 of 0.08 mol dm-3 hydrochloric acid using 1.00 mol dm-3 hydrochloric acid I must find out how much of the acid, and therefore how much distilled water, I should add to the graduated flask for a 250cm3 solution.

  2. Chem Lab report. Objective: To determine the concentration of potassium manganate(VII) solution using ...

    Thus, the volume of potassium manganate(VII) solution would be smaller. To reduce this error, it was suggested to heat up 35cm3 of water to 60? using a thermometer first, so that the required temperature could be felt by palm and a more accurate temperature could be taken when heating the mixture of ethanedioic acid and sulphuric acid.

  1. Determination of Total Hardness in Water by EDTA Titration

    of mole of EDTA used = 0.00512M x 0.01993 = 0.000102 mole From the equation, mole ratio of EDTA: M2+ = 1:1 The no. of mole of M2+ ions in 25ml of a unknown sample = 0.000102 mole The molar mass of EDTA (i.e.

  2. THERMOMETRIC TITRATION

    Handling Acids: Sodium hydroxide: sodium hydroxide is very corrosive and can * Cause severe burns * Cause permanent eye damage * Be very harmful if ingested Hydrochloric Acid (HC l): HCl is very toxic and can cause following damage: * Concentrated HCl can form mists.

  1. Titration Experiment Write Up

    1 mole of HCl to produce 1 mole of NaCl and 1 mole of water. Therefore, the number of moles of HCl (with concentration of 1 mol/dm3) present in 25 cm3 would be number of moles of NaOH used to neutralise it.

  2. Essay on the Oxides of Period 3 Elements

    The solubility of a substance is related to the similarity in bond strength in the solvent and the solute (water and silicon dioxide in this case). The extensive network of covalent bonds is much stronger than the water-water interactions (hydrogen bonds).

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