At l=530 nm:aCuSO4=7.544L/mol-cm aKMnO4= 3.645 L/mol-cm
At l=800nm: aCuSO4=2.908L/mol-cm aKMnO4= 5.412L/mol-cm you use a celleith a path length of 1.0cm
An unknown solution containing both CuSO4 and KMnO4 gave an absorbance reading of 0.679 at 530nm and an absorbance of 0.525 at 800nm. What is the molar concentrations of KMnO4 and CuSO4 in your unknown?
To find the molar concentrations of KMnO4 and CuSO4 in the unknown solution, we can use the Beer-Lambert Law, which relates the absorbance of a solution to its concentration and the path length of the cuvette.
The Beer-Lambert Law is written as follows:
A = ε × c × l
Where:
A = Absorbance
ε = Molar absorptivity (also known as molar absorptivity coefficient)
c = Concentration of the solution
l = Path length (the distance the light travels through the solution, usually given in cm)
For CuSO4 at 530 nm:
A_CuSO4_530nm = ε_CuSO4_530nm × c_CuSO4 × l
For KMnO4 at 530 nm:
A_KMnO4_530nm = ε_KMnO4_530nm × c_KMnO4 × l
For CuSO4 at 800 nm:
A_CuSO4_800nm = ε_CuSO4_800nm × c_CuSO4 × l
For KMnO4 at 800 nm:
A_KMnO4_800nm = ε_KMnO4_800nm × c_KMnO4 × l
Given:
A_CuSO4_530nm = 0.679
A_KMnO4_530nm = 0.525
A_CuSO4_800nm = 0.679
A_KMnO4_800nm = 0.525
l = 1.0 cm
Molar absorptivity at 530nm:
ε_CuSO4_530nm = 7.544 L/mol-cm
ε_KMnO4_530nm = 3.645 L/mol-cm
Molar absorptivity at 800nm:
ε_CuSO4_800nm = 2.908 L/mol-cm
ε_KMnO4_800nm = 5.412 L/mol-cm
Now we can substitute the given values into the equations:
0.679 = 7.544 × c_CuSO4 × 1.0
0.525 = 3.645 × c_KMnO4 × 1.0
0.679 = 2.908 × c_CuSO4 × 1.0
0.525 = 5.412 × c_KMnO4 × 1.0
We can solve these equations to find the molar concentrations of CuSO4 and KMnO4 in the unknown solution.