[parywinkle]

Beer lambert law question?
100 ml of a solution contains 0.050 g of a coloured compound that absorbs exactly half the incident light intensity at 500 nm when the solution is in a 1.00 cm wide spectrophotometer cell. The cell width that would absorb 75% of the incident light intensity is:

a. 0.5 cm
b. 1.0 cm
c. 2.0 cm
d. 4.0 cm
e. (log 10 2) cm
f. none of the above


The mass of the coloured compound in the same solution as in question 1 above that would have an absorbance of 1.5 in the same 1.00 cm cell is (in grams):

a. 0.050
b. 0.075 log10 2
c. 0.033 log10 2
d. 0.075 / log10 2
e. 0.075 / log10 0.5
f. none of the above

----

For the first question, I used A = log (Io/I) = E c l where E c is constant and solved for l. I got 2.0cm.

for the second question, I do not have much idea on how to approach it.
how would you rearrange the equation?