Question

Can you tell if Beer's Law holds for your stock solutions as well as in the calibration range? Why or why not?

(P.S. this is a lab question and Beer's Law equation is: A(absorbance) = a(absorptivity) x b(path length) x c(concentration))

Answer 1

I'm confused by the language of "Can you tell if". Did you run any experiments specifically for this? If the dilute solutions follow Beer's Law and the stock solutions are not too concentrated, they may follow Beer's Law also. Generally, however, concentrated solution do not follow Beer's Law and the more concentrated they are the more they deviate from Beer's Law.

Answer 2

Yes we did ran an experiment for this but I was confused as to how I could find the stock solution absorbance. Here's the data I had obtained:
- Unknown solution absorbance: 0.271
- Kool-Aid flavor: Cherry
- Wavelength = 470nm
- Mass of mix 1 transferred = 4.1378g
- Volume of stock solution = 1000mL

Answer 3

And the net weight for that is 3.6g (I'm not sure how to use it)

Answer 4

I would have measured the absorbance.
Did you have a working curve; e.g., absorbance measurements of several solutions of different concentrations.
They look like this.
https://www.google.com/search?q=graph+beer%27s+law&client=firefox-a&hs=bnu&rls=org.mozilla:en-US:official&channel=sb&tbm=isch&imgil=mdlUrxcchZpe8M%253A%253BW7kfg84I6VBiYM%253Bhttp%25253A%25252F%25252Fwww.ic.sunysb.edu%25252FClass%25252Fche133%25252Flectures%25252Fbeerslaw.html&source=iu&pf=m&fir=mdlUrxcchZpe8M%253A%252CW7kfg84I6VBiYM%252C_&usg=__qd4xkMciBFeGHOfXSwOclBn7coE%3D&biw=1024&bih=609&ved=0CCsQyjc&ei=0k1uVJT8DIGNgwTk74KoCg#facrc=_&imgdii=_&imgrc=mdlUrxcchZpe8M%253A%3BW7kfg84I6VBiYM%3Bhttp%253A%252F%252Fwww.ic.sunysb.edu%252FClass%252Fche133%252Flectures%252Fbeerdimer.jpg%3Bhttp%253A%252F%252Fwww.ic.sunysb.edu%252FClass%252Fche133%252Flectures%252Fbeerslaw.html%3B889%3B607

Answer 5

I wanted to get that graph but I didn't know how to find the concentration. Only way I can plot it is using concentration and absorbance

Answer 6

Isn't that all you need? Plot A vs C. You get concentrations from the volume of the stock solution diluted to x mL.

Answer 7

Well i have the dilution (mL/100mL) and absorbance. So to get concentration do I take the dilution and divide it by the volume of stock solution I used?