00:01
So for this question, we have the absorbance of a solution of copper ion decreases by 45%.
00:09
So what we have to look at is that according to beer's law, absorbance, which is the a, is going to change directly proportional to the concentration.
00:21
So if the absorbance decreases by 45%, so does the concentration decrease by 45%.
00:33
So if it decreases by 45%, then that means that 55 % is what's left.
00:41
So that means that the concentration of the copper ion has to now be 55 % of what it was originally.
00:56
Well, we're told that we had 15 .0 milliliters of a 1 .00 molar solution.
01:06
So if 55 % is left, then that means that it's going to be 55 % of 1 molar is left, which means that's going to have a concentration of 0 .55 molar.
01:22
Well, it wants to know how much water was added in order to change its concentration to 0 .55 molar...