To determine the concentration of the dye that corresponds to an absorbance of 0.140, we can use Beer’s Law. Beer’s Law, also known as the Beer-Lambert Law, states that the absorbance (A) of a solution is directly proportional to its concentration (C) and the path length (l) of the light through the solution. This relationship can be expressed with the formula:
A = εlc
Where:
- A = absorbance
- ε = molar absorptivity (a constant that depends on the substance and wavelength)
- l = path length of the sample (usually in cm)
- C = concentration of the solution (usually in mol/L)
To find the concentration (C) that corresponds to an absorbance (A) of 0.140, you would first need the values of the molar absorptivity (ε) and the path length (l). If these values are known, you can rearrange the formula to solve for C:
C = A / (εl)
Plugging in the known absorbance (0.140), along with the values for ε and l, will give you the concentration of the dye. If you do not have those values, you can plot a graph of absorbance versus concentration using experimental data. By plotting the absorbance on the y-axis and concentration on the x-axis, you can establish a straight line according to Beer’s Law. From this graph, you can then find the point where the absorbance is 0.140 and read off the corresponding concentration.
In summary, Beer’s Law emphasizes the linear relationship between absorbance and concentration, enabling us to determine the concentration of a substance in solution by measuring its absorbance.