Our colorimeter and spectrometer already calculate absorbance and $\%T$ for us$,$ but it is based on initial light intensity, $I_0,$ and final light intensity, I, values. Refer to Equations $1$ and $2$ of the Intro to Spectroscopy: Finding the Analytical Wavelength lab.

Calculate the $\%T$ and A for a solution of yellow dye that has $I=60$ and $I_o=255.$ Show the work for your calculations.

$\%T=(\frac{60}{255})100\%$~~$23\mathrm{.}53$

$A=-log10(23\mathrm{.}53\%)$

~~$0\mathrm{.}62$

a$.$ A sample of fruit punch containing Red #$40$ dye is found to have $37\mathrm{.}2\%$ transmittance. Calculate its concentration using your results from this lab.

b$.$ Picture that this fruit punch sample was not the original, but a dilution prepared from $2\mathrm{.}00mL$ of the actual fruit punch with $8\mathrm{.}00mL$ of water. Calculate the original concentration of the fruit punch.

If you were trying to analyze a sample that had a low molar absorptivity value and was not very soluble $($implying that you could not make a highly concentrated solution of it$),$ is there any way that you be able to use spectroscopy to analyze it$?$ Explain your answer.

Discussion: On a separate sheet, write a summary of the main concepts and results from this lab. Critique your data. Are there any points on the graph that don't seem to fit? Discuss possible reasons for any discrepancies. $($Remember to write a paragraph rather than bullet points about analysis, sources of error and theory$/$concepts explored$)$

$5$

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