An unknown was prepared with the concentration of 0.000630 M. A Beer's Law plot was prepared using the absorbance values from standard solutions of ASA and a line drawn through all the points passed through the origin with a slope of 1550.2 M–1. The expected absorbance and %T values for the diluted aspirin solution prepared by the student is ________ and __________, respectively.
To find the expected absorbance and %T values for the diluted aspirin solution, we can use Beer's Law equation: A = εbc, where A is the absorbance, ε is the molar absorptivity (or molar extinction coefficient) in M^(-1)cm^(-1), b is the path length in cm, and c is the concentration in M.
Given:
- Concentration of the unknown solution = 0.000630 M.
- Slope of the Beer's Law plot = 1550.2 M^(-1).
Since the line drawn through all the points passes through the origin, it means that at 0 concentration, the absorbance is 0.
So, we can rewrite Beer's Law equation as: A = εc
We know that the slope (1550.2 M^(-1)) of the line is equal to εb (ε x 1), where b = 1 cm (path length).
Therefore, εb = 1550.2 M^(-1)
ε x 1 = 1550.2 M^(-1)
ε = 1550.2 M^(-1) / 1 cm
ε = 1550.2 M^(-1)cm^(-1)
Now that we have the value of ε, we can calculate the absorbance and %T for the diluted aspirin solution.
Absorbance (A) = εc
A = (1550.2 M^(-1)cm^(-1)) x (0.000630 M)
A ≈ 0.976
To calculate %T (percent transmittance), we can use the formula: %T = 100 - A
%T = 100 - 0.976
%T ≈ 99.024
Therefore, the expected absorbance for the diluted aspirin solution is approximately 0.976 and the expected %T value is approximately 99.024.