An unknown was prepared with the concentration of 0.000520 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
I answered this just a few posts back but the molarity was different.
Absorbance = slope x C will get A.
Then A = log (1/T) will get transmittance.
transmittance x 100 = %T.
To determine the expected absorbance and %T values for the diluted aspirin solution, we first need to use Beer's Law equation, which relates the concentration of a solution to its absorbance:
A = εlc
Where:
- A is the absorbance
- ε (epsilon) is the molar absorptivity (also known as the molar extinction coefficient) in M^-1 cm^-1
- l is the path length of the cuvette (usually 1 cm)
- c is the concentration of the solution in M
Given that a Beer's Law plot was prepared and passed through the origin with a slope of 1550.2 M^-1, we can determine the molar absorptivity (ε). The slope of the plot represents ε times the path length (εl), so we can calculate ε as follows:
slope = εl
1550.2 M^-1 = ε * 1 cm
Therefore, the molar absorptivity (ε) is 1550.2 M^-1 cm^-1.
Now, we can use the molar absorptivity and the concentration of the solution to calculate the absorbance (A) using Beer's Law equation.
A = εlc
A = (1550.2 M^-1 cm^-1) * (1 cm) * (0.000520 M)
Calculating the value, we find that the absorbance (A) is 0.8067.
To calculate the percent transmittance (%T), we can use the following equation:
%T = 100 * 10^(-A)
%T = 100 * 10^(-0.8067)
Calculating the value, we find that the percent transmittance (%T) is approximately 19.1%.