What is the concentration of an unknown potassium dichromate solution with an absorbance of 1.603 at 345nm? (The path length is 1 cm, molar absorptivity constant = 0.412 A.mol-1.cm-1 )
A = abc
You know A = 1.603
You know a = 0.412
You know b = 1 cm
Solve for c.
To determine the concentration of the unknown potassium dichromate solution, you can use the Beer-Lambert Law, which relates the absorbance of a solution to its concentration.
The Beer-Lambert Law equation is as follows:
A = ε * c * L
Where:
A = Absorbance
ε = Molar absorptivity constant
c = Concentration
L = Path length (in cm)
Given:
Absorbance (A) = 1.603
Path length (L) = 1 cm
Molar absorptivity constant (ε) = 0.412 A.mol-1.cm-1
To find the concentration (c), rearrange the equation as follows:
c = A / (ε * L)
Substitute the given values into the equation:
c = 1.603 / (0.412 * 1)
Calculate the concentration:
c = 1.603 / 0.412
c ≈ 3.89 mol/L
Therefore, the concentration of the unknown potassium dichromate solution is approximately 3.89 mol/L.
To find the concentration of the unknown potassium dichromate solution, you can use the Beer-Lambert Law. The Beer-Lambert Law states that the absorbance of a solution is directly proportional to the concentration of the absorbing species and the path length of the sample.
The equation that represents the Beer-Lambert Law is:
A = ε * c * l
Where:
A is the absorbance of the solution.
ε is the molar absorptivity constant.
c is the concentration of the solution.
l is the path length of the sample.
In this case, we are given the values of absorbance (A = 1.603), molar absorptivity constant (ε = 0.412 A.mol-1.cm-1), and path length (l = 1 cm). We need to find the concentration (c) of the unknown potassium dichromate solution.
Rearranging the equation, we have:
c = A / (ε * l)
Substituting the given values, we get:
c = 1.603 / (0.412 * 1)
Simplifying the calculation:
c = 1.603 / 0.412
Using a calculator, we find:
c ≈ 3.890 mol/L
Therefore, the concentration of the unknown potassium dichromate solution is approximately 3.890 mol/L.