Dear Arkcon;
I don’t believe that the “Error-Bars” will be very helpful, because:
.. differences in light intensity by less than 1%.
- is not very linear to Absorptions, but Absorptions is “very” linear to Concentrations!
That means that the “’1.0 %’ -Error-Bars” will have a different size over de whole Absorptions scale.
Dear 1stPlace;
As the second Question asks:
Using the above data, calculate the minimal concentration .
- it is required to solve prior the first Question, otherwise you will not have any Concentration result!
To solve the 1. Question you best “see” the Spectrometer as only a little special Indicator!- - So, at how much mL’s your “Indicator” has changed its color?
- - And the remaining you can handle as a normal “…….”-Titration: It’s Stoichiometry!
Then to solve the 2. Question you need the Mrs. “Beer and Lambert”, because you will have to translate:- - Your Concentration and corresp. Absorption you have read from the Graph into an of εtotal!
- - 1.0% Transmittance into its corresponding Absorption (A1.0%).
- - Finally you can translate your A1.0% with the help of εtotal into a Concentration.
Mrs. “Beer and Lambert” with Graphs, Formulas, and Explanations you can find on:
"Corrected Beer-Lambert Law (http://www.p-forster.com/English/themes/Spectroscopy/BASICS/Corrected Beer's Law.htm)”.
I hope this gives you enough help to start your both Solutions.
Good Luck!
ARGOS++
P.S.: For Stoichiometry the following page may be of some help: "Stoichiometry Problem (http://www.chemicalforums.com/index.php?topic=23025.0)”
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