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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: ozzlomo on May 06, 2009, 01:36:43 PM

Title: Beer's Law Plot
Post by: ozzlomo on May 06, 2009, 01:36:43 PM

If for example, on an exam, a teacher were to give students a Beer's law plot (graph), with absorbance on the y axis, and concentration in ppm on the x axis. The teacher gives the equation of the graph in the form y = mx + b, or y = .800x, for example. If the teacher asked for the absorbance, and gave the ppm value or the y-axis values, you would simply plug the values into the equation, and solve for y or x depending on what value he gave you, and that would be absorbance correct? If he asked for transmittance, then that would 10^-abs (ten to the negative absorbance). Please correct me if I am wrong.

Title: Re: Beer's Law Plot
Post by: ARGOS++ on May 06, 2009, 02:27:40 PM

Dear ozzolomo;

All looks ok, except:

Quote from: ozzlomo on May 06, 2009, 01:36:43 PM

If the teacher asked for the absorbance, and gave the ppm value or the y-axis values, you would simply plug the values into the equation, and solve for y or x depending on what value he gave you, and that would be absorbance correct?

Correct:   . the x-axis values .   and:     . for y on x  ..

Good Luck!
                    ARGOS⁺⁺

Title: Re: Beer's Law Plot
Post by: ozzlomo on May 06, 2009, 02:58:18 PM

Or if he gave you the y-axis values, you would plug it into the equation, and solve for x. Right?

Title: Re: Beer's Law Plot
Post by: ARGOS++ on May 06, 2009, 03:02:19 PM

Dear ozzolomo;

That’s right, but then you get not absorbance, then you solve for concentration.

Good Luck!
                    ARGOS⁺⁺