A student, who did the titration correctly according to the procedure, calculate

Question

A student, who did the titration correctly according to the procedure, calculated his molar mass for his unknown acid to be 1.56 times 10^-3 g/mol. Another student calculated her molar mass to be 85 g/mol. Should the first student be concerned given that the samples of unknown acids were all different from each other? explain. A student had D1 water clinging to the inside of her burette and, in the interest of time, omitted rinsing her burette with titrant before beginning the experiment. What affect, if any, would this have on the calculated molar mass for the first trial? Explain clearly indicating if the molar mass calculated by this student would be high, low or unaffected by this omission. While determining the molar mass, an air bubble came out of the burette tip midway through the titration. This bubble had been in the burette since the initial reading, but was underacted. Explain clearly how this would affect, if at all, the calculated molar mass of the unknown, specifically if the calculated molar mass would be incorrectly high, low or unaffected. If you were given an unknown diprotic acid (and you thought it was a monoprotic acid), would your molar mass calculations still be correct? If not, explain clearly what affect this would have on your calculations indicating whether the calculated molar mass would be higher or lower than the true molar mass and by what factor.

Explanation / Answer

1) Molar mass of any substance or element cannot be less than 1 g/mol which is the lowest for an element she has reported as 1.56 * 10-3 g/mol which is not possible so she should be concerned about her value she should have done mistake somewhere.

2) if she had water molecule clinging to buret then it will also add to the titrant making it one or two drops less and replacing the base and thereby increasing the equivalence point of titration hence it will lead to overestimation of no. of moles of acid that we have taken which will lead to underestimate the molar mass of acid. as molar mass is inversely proportional to no. of moles. hence molar mass will be low because of this omission

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