A student determines the percent transmittance of a solution of Red 3 at 600 nm at concentrations as follows
Concentration is 8.0 mg/L and Transmittance is 29.6, How do you find the absorbance?
2007-06-04 08:53:16 · 3 answers · asked by Christie 1 in Science & Mathematics ➔ Chemistry
Transmittance will be a percentage or %T so to get in absolute unit you first divide %T/100 to To
To = %T/100 = 0.296
A = -log(To)
A = -log(0.296) = 0.53
ref: http://en.wikipedia.org/wiki/Transmittance
2007-06-04 09:03:43 · answer #1 · answered by Dr Dave P 7 · 0⤊ 0⤋
Presumably what was used was a spectrophotometer. What this instrument does is shine a light through a solution in a special tube, then measures how much light was absorbed by the solution, and how much was transmitted through the solution to something that measures the light behind the tube. The light can't go anywhere else, so anything not transmitted must have been absorbed. If transmittance is 29.6%, then absorbance was 70.4%.
2007-06-04 15:59:34 · answer #2 · answered by kt 7 · 1⤊ 1⤋
hopefully this will let you work it out:
the total radiation that is supplied is split into two parts. Part of it is absorbed, and part is transmitted. Total - transmitted = absorbed. use E=hf, c=[lambder]f and [ ] = n/v
2007-06-04 16:02:02 · answer #3 · answered by jgdyrh 2 · 0⤊ 0⤋