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Assessed Practical Titration Write-up

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Introduction

Assessed Practical Titration Write-up Equation: Na2CO3 + H2SO4 --> Na2SO4 + CO2 + H2O One mol of Na2CO3 reacts with one mol of H2SO4. Results: The weight of my sodium carbonate crystals was 2.67g and the results of the titrations are as follows: Rough 1st 2nd 3rd 4th 5th 6th Initial Reading 00.00 00.50 00.00 00.00 00.00 00.00 00.20 Final Reading 26.45 26.45 26.05 27.00 25.85 25.90 26.10 Titration 26.45 25.95 26.05 27.00 25.85 25.90 25.90 pH slightly acidic neutral slightly acidic slightly acidic slightly alkali neutral neutral So the average of the closest three titration results are is: 25.95 + 25.90 + 25.90 / 3 = 25.92 The mass of Na2CO3 I used is 2.67g and the relative molecular mass of Na2CO3 is 106. So the number of mols of Na2CO3 I used was: 2.67 / 106 = 0.0251 mols in 250 cm3 So the concentration of the Na2CO3 solution was: 0.1004 mol dm-3. ...read more.

Middle

It is then possible that when I was dissolving the Na2CO3 crystals in distilled water in the beaker, I may have spilt a few drops on the floor or left some on the glass rod or in the bottom of the beaker when I poured it into the graduated flask. This would mean that some of the Na2CO3 would have been lost, which would in turn affect my results. Another possible source of possible error is when it comes to reading the burette. Each time I took a reading, I lowered the burette to eye level and held a piece of white paper up behind it. It is however still possible that I accidentally misread one of the readings, which would again affect my results, as my calculations would all be incorrect. ...read more.

Conclusion

There is a level of uncertainty on all measurements that I make because the are subject to human error. The percentage errors for the main different parts of the experiment are as follows (using the equation: error x 100 / reading): Balance: 0.18 % Volumetric Flask: 0.08% Burette: 0.19% Pipette: 0.24% As you can see, the percentage errors here are very small, but, to take the example of the pipette, the volume error is 0.06cm3 - which means that if I fill up to 25cm3 then the real value could be between 24.94cm3 and 25.06cm3. This could make a difference in my calculations. One way to help minimise the percentage error is by using larges quantities of substances, as this would decrease the amount by which you can go wrong. I feel that I was fairly accurate in my procedure and I am happy with how it went and I believe my result to be accurate. ?? ?? ?? ?? Thom O'Dell ...read more.

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