you are given a bottle that contains a pure solid for which you must determine t

Question

you are given a bottle that contains a pure solid for which you must determine the e value at a particular wavelength. you know its molecular weight, and it is sufficiently soluble in the chosen solvent. you have a spectrophotometer of excellent quality. in spite of all this, the e value will have some degree of error. In order to gauge the reliability of e, you need to know the precision of two different measurements that must be used to compute e. what are these measurements? (they are not related to the spectrophotometer. Think about what physical operations you have to do in the lab to prepare the necessary solutions of the solid.)

Explanation / Answer

First we write down the equation of Beer Lambert's law which is used to determine the e-value of different compounds.

A = e*l*C

Here, 'l' is the length of the cuvette, and C is the concentration of the analyte solution

Since we have been told that the spectrohpotometer is excellent, and the two measurements are not related to it, so factor out the term 'l' from our consideration.

Next, we are left with the term 'C'.

C = (m/M)/V

Here, m is the mass of the analyte you take, M is the molecular mass which is known to us and V is the volume of the solvent taken to form the mixture.

So the two measurements whose precision must be known to gauge the reliability of e-value are:

Mass of the solid taken, and volume of the solvent taken.

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