Estimating the % purity of marble by back titration method Essay

The values for the % rightness of stain that I have cypher lie in a close range, however there is a significant difference, of 4.74% in the purity estimated between the 2 individual values. Nonetheless, the recreation is ski bindinged by the uncertainty of 4.84%. However, certain errors have occurred that have caused this parenthesis in the final results.REASONS FOR DEVIATIONRandom Errors1. Loss of marble later on weighing After weighing out the marble, there is a excellent loss in mass in transferring the mass from the butter authorship used for weighing as a small quantity of the okay powdered marble sticks to the butter paper and does not react with the HCl at all. Also, while transferring the busted CaCO3 whatsoever particles could have also been blown out-of-door by the wind. Thus the disparity in the masses used could mea indisputable for the different values obtained.2. HCl left in the pipette being a manual instrument, there is no definite way of making sure tha t each and e really drop of the acid that was measured has been transferred to the conical flask, this reduces the leger of acid used and such a change in each one of the reading allow for directly affect the value of the % purity.3. disperse bubbles in pipette dispenser For this experiment, due to the corrosive nature of the concentrated acid, a pipette dispenser was used to measure out the HCl. However there were some air bubbles that were trapped that cause an error in the volume of HCl that is not accounted for by the absolute uncertainty of the pipette.Systematic Errors1. Unevenly crushed marble The CaCO3 provided was not evenly crushed some was still in larger chunks while the rest was finer granules. This non-uniformity in the texture of CaCO3 also creates a different develop area for the acid to react with and this can be the cause of the differing values of purity.2. Excess NaOH added in titration While titrating the HCl and the HCl + CaCO3 ascendents the usage of th e phenolphthalein exponent causes an error in the amount of alkali added as the titration is only stop once the colour changes to a pale pink, this firstly is a very qualitative and subjective instruction and also the indicator on crook pink indicate a slight alkalinity. Hence, the actual neutralization lead was left behind 1-2 drops back.3. Unevenly distributed impurities CaCO3 is found naturally as marble in the earth. Thus, being a natural stone the impurity that it get out contain will be randomly distributed and due to this unevenness, the purity will vary with every sample.IMPROVEMENTS TO PREVENT AFOREMENTIONED ERRORS1. Keep fans and windows shut and cover CaCO3 while transporting By doing this one can minimize the loss of particles and thence reducing the uncertainty.2. Carefully using apparatus to avoid human errors By practice and careful usage one can eliminate the errors caused by the air bubbles in the pipette, errors in transfer and parallax.3. Marble should be cr ushed evenly the CaCO3 should all be of the same texture so that the surface area is kept controlled and this will reduce the disparity in the purity values that have been caused by the differing surface areas.4. Using another indicator that prevents uncertainty in the exact occlusion of neutralization If a solution like Universal Indicator is used then the exact point when the titration is complete can be easily identified and thus by eradicating this error, one can aim to reduce the disparity observed in the readings.