Question

A) The equation for your line has a nonzero y-intercept. Beer’s law does not have an analogous term. Explain the discrepancy between your experimental best fit equation and the theoretical Beer’s law equation.

B) Consider the experimental procedure. What were the most likely sources of error? Remember that experimental error is not the same thing as a calculation mistake or incorrectly following the procedure.

C) In a previous experiment we used the λmax to determine the absorbances to use for the calibration graph. Why did we other criteria (not λmax) in this experiment? Is Beer’s law valid at other wavelengths? Explain.

D) Based the absorbance vs. wavelength spectrum of the dissolved brass solution, is there evidence of the presence of elements other than copper and zinc in the brass sample? Explain your answer.

Answer 1

A) According to Beer's law A=-log T, T for transmittance

For no intercept or zero intercept it means 100% transmittance and this is the case only for zero concentration means pure solvent.Because according to Beer's law A=Klc, length and can not be zero only c can be zero for absorbance vs concentration graph.

B) 1) calibration of instrument

2) maximum wavelength set up

3) selection of solven

4) setting of filters

5) proper cleansing and adjustment of instruments also works

C) we can have absorbance curve at any wavelength but without maximum wavelength selection we cant name that as maximum absorbance.