Chemistry SL and HL Questions on Uncertainties and errors in Measurements and Results , chemistry homework help

1.541 ± 0.001 g of hydrated oxalic acid crystals were dissolved in distilled water. The solution was placed in a 250.0 ± 0.5 cm3 volumetric flask and the total volume made up to the mark with distilled water. After thoroughly mixing the contents, 25.00 ± 0.04 cm3 of this solution was pipetted into a conical flask. This required 24.90 ± 0.08 cm3 of 0.100 ± 0.001 mol dm3 sodium hydroxide solution to be neutralised completely.

The equation for the reaction is:
(COOH)2(aq) + 2NaOH(aq) ↓ (COONa)2(aq) + 2H2O(l)

  1. (a) Calculatethepercentageuncertaintyassociatedwith:
    1. (i) the mass of the oxalic acid.
    2. (ii) the solution in the volumetric flask.
    3. (iii) the volume in the pipette.
    4. (iv) the molarity of the sodium hydroxide solution.
    5. (v) the volume of sodium hydroxide solution used.
  2. (b) Calculatethetotalpercentageuncertaintyforthisexperiment.
  3. (c) Calculate the molar mass of the oxalic acid obtained from these experimental results to thecorrect number of significant figures and state the uncertainty.
  4. (d) Thecorrectliteraturevalueforthemolarmassoftheacidis126.06gmol-1.Calculatethepercentage error.
  5. (e) State any other assumptions which may have affected the accuracy of the result.

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