Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: ViktorDL on April 13, 2022, 06:33:34 AM

Title: Spectrophotometry problem
Post by: ViktorDL on April 13, 2022, 06:33:34 AM

I am concerned in how to do an exercise, because I don't actually know how to do it:
A 0.0500 M solution, whose solute has a molecular weight of 230, gives a reading of transmittance of 35% when using a cuvette with a path length of 1 cm and a length 270nm wave. Calculate the absorptivity

I've tried doing it before, but because I don't pay atention in class I have no formulas nor notes, my fault, but I can't ask the teacher anymore since it's Easter, thanks a lot in advance

Title: Re: Spectrophotometry problem
Post by: Babcock_Hall on April 13, 2022, 09:07:01 AM

Do you have a textbook?

Title: Re: Spectrophotometry problem
Post by: ViktorDL on April 13, 2022, 12:07:35 PM

None at all, I only have like a pdf, but it doesn't say anything on how to do it, it's only graphs of the curve and all that, other than that there's like a web page that was given to us by the teacher, but the same, I'm sorry I can provide such little source

Title: Re: Spectrophotometry problem
Post by: Orcio_87 on April 13, 2022, 02:53:33 PM

@ViktorDL Did you try using the google ?  Like - searching for transmittance vs. absorbance relation ?

Title: Re: Spectrophotometry problem
Post by: Babcock_Hall on April 13, 2022, 05:29:44 PM

You will need to be careful about how you express the transmittance.  Sometimes the formula to convert it to absorbance is written for the fraction of transmittance (a number between zero and one), and sometimes this formula is written for transmittance in percentage terms (0 to 100% T).