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

Analysing aspirin tablets.

Extracts from this document...

Introduction

Topic: Analysing aspirin tablets. I familiarised myself with the Material Safety Data Sheets of toxic substances. PLANNING (A) Aspirin1, or acetylsalicylic acid is a drug in the family of salicylates, often used as an analgesic (to relieve minor aches and pains), antipyretic (to reduce fever), and as an anti-inflammatory. It also has an antiplatelet ("blood-thinning") effect and is used in long-term, low doses to prevent heart attacks and cancer. figure 1 figure 2 Aspirin tablets consist mainly of 2-ethanoylhydroxybenzoic acid (acetylsalicylic acid, CH3COOC6H4COOH, figure 3). figure 3 Although the acidic conditions found in stomach do not affect aspirin, the alkaline juices in the intestines hydrolyse it to ethanoate (acetate) ions and 2-hydroxybenzoate ions. CH3COOC6H4COOH + 2OH- � CH3COO- + HOC6H4COO- + H2O Aim: To determine the percentage of CH3COOC6H4COOH in aspirin tablets. Hypothesis: When a known amount of standard sodium hydroxide solution is used in excess to hydrolyse a known mass of aspirin tablets, we may determine the percentage of acetylsalicylic acid in those tablets. Prediction: The quantity of acetylsalicylic acid will be smaller than the one given on the packaging and in the leaflet enclosed. PLANNING (B) Requirements: - 3 aspirin tablets (Acidium acetylsalicylium 500 mg) - pipette (25 cm3) ...read more.

Middle

DATA COLLECTION Mass of 3 aspirin tablets/ g 1.8 Mean mass of one tablet/ g 0.6 Titration number Rough Accurate 1 Accurate 2 Final burette reading/ cm3 1 1.4 1.3 Initial burette reading/ cm3 0 0 0 Volume of 0.10 mol dm-3 HCl added/ cm3 24.0 23.6 23.7 Mean volume of HCl added 23.8 V c n NaOH 25 cm3 = 0.025 dm3 ? ? HCl 23.8 cm3 = 0.023.8 dm3 0.10 mol dm-3 0.00238 mol DATA PROCESSING AND PRESENTATION * Standardisation of the approx. 1.0 mol dm-3 NaOH During titration the reaction below takes place: HCl(aq) + NaOH(aq) � NaCl(aq) + H20(l) That is why the solution changes its colour from pink into transparent. The ratio between HCl and NaOH is 1/1, so one mol of HCl reacts with one mol of NaOH. n = c � V NaOH VNaOH = 25 cm3 = 0.025 dm3 cNaOH = ? nNaOH = nHCl HCl VHCl = 23.8 cm3 = 0.0238 dm3 cNaOH = 0.10 mol dm-3 nNaOH = 0.10 mol dm-3 � 0.0238 dm3 = 0.00238 mol 1. From the balanced chemical equation find the mole ratio NaOH:HCl 1:1 2. Find moles HCl NaOH: HCl is 1:1 So n(NaOH) = n(HCl) = 3 x 10-3 moles at the equivalence point 3. ...read more.

Conclusion

burette: 0.5% 4. calibrated flask: 0.2% Total: 0.92 % CONCLUSION AND EVALUATION As we can see from the results above, the prediction made at the very beginning of this lab was correct. Neither type of acid or base nor the concentration of acid does not have influence on the enthalpy of neutralisation. Hence we may assume that the enthalpy of neutralisation is equal to the enthalpy change for H+ + OH-� H2O. The enthalpy change for this reaction, however, is -57.9 kJ mol-1. The differences between my results and the theoretical value may come from the fact that the measurements were not very accurate. The temperatures of the acids, bases and mixtures might have been influenced by cool beakers. Therefore the temperatures were a bit lower than they should have been. If the ?T was higher by 3oC, the enthalpy of neutralisation would be almost the same as in the sources. I do not know how to improve the experiment so that data gathered will be similar to theoretical values. I reckon in classroom conditions such mistake is not a serious one. SOURCES: 1. Green J, Damji S. 2001. Chemistry. Second edition. IBID Press, Victioria, Australia. 2. http://en.wikipedia.org/wiki/Standard_enthalpy_change_of_neutralisation http://en.wikipedia.org/wiki/Aspirin 1 The definition comes from http://en.wikipedia.org/wiki/Aspirin Figures 1 and 2 come from http://en.wikipedia.org/wiki/Aspirin Figure 3 comes from http://home.caregroup.org/clinical/altmed/interactions/Images/Drugs/aspirin.gif ANALYSING ASPIRIN TABLETS 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous 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 GCSE Aqueous Chemistry essays

  1. Marked by a teacher

    Enthalpy of Neutralisation.

    3 star(s)

    When this number is scaled to a molar quantity, it is called the enthalpy change of the reaction, ?H. Reactions between liquids and solids are easily carried out in such a device or a reaction may be carried out externally (as in the experiment)

  2. Determine the percent aspirin in an aspirin tablet and to compare this with the ...

    Label information for the aspirin. Stated dose of one tablet = 300 mg Average weight of one tablet = 328 mg Other ingredients; Maize starch 3. Weight of aspirin taken for analysis. Weight Of Empty Container (g) 123.1721 Weight Of Container And Aspirin (g) 124.8140 Weight Of Aspirin (g) 1.6419 Note: Five tablets were used.

  1. Indigestion Tablets Investigation

    The formula for the reaction of Calcium Carbonate and Magnesium Carbonate are the similar because calcium and magnesium have the same electrovalencies. This is shown below. calcium + hydrochloric --> calcium + water + carbon carbonate acid chloride dioxide "CaCO3 + 2HCl --> CaCl2 + H2O + CO2"(page 216)

  2. Investigation into the efficiency of various indigestion tablets.

    These can then be digested and egested through the digestive system. The easiest way of solving my problem would be to use titration. In the burette I would put my known substance - the titrant - 1M HCl.

  1. Investigation in to discover the percentage of acetylsalicylic acid in a sample of aspirin ...

    - This will neutralise the sodium hydroxide � Distilled Water - This is used to make up the correct solutions and to wash equipment. Normal water will not do because of the impurities in it. � Methyl Orange indicator - The colour of this indicates when the sodium hydroxide has been neutralised by the hydrochloric acid.

  2. Preparation of aspirin - The chemical background This is the overall reaction that ...

    The esterification reaction occurs extremely slowly unless an acid catalyst is present. The mechanism of the reaction: Protonation of carbonyl oxygen- the carbonyl oxygen takes a proton from the catalyst acid double , then the proton (hydrogen ion) becomes attached to one of the lone pairs on the oxygen which is bonded to the carbon.

  1. Analysis of the content in Aspirin Tablet

    After all, the contents in the conical flask would be transferred into a volumetric flask with more distilled water for dilution, so the amount of distilled water added was not that important to be accurate. Moreover, after warming the mixture in the conical flask, it ought to be cooled down,

  2. Making Aspirin.

    Aspirin (either 81 mg or 325 mg daily) is indicated in the following conditions: * Unstable angina (acute coronary syndrome). * Acute myocardial infarction. * Secondary prevention of myocardial infarction * Secondary prevention of stroke (carotid or primary cerebrovascular disease).

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