We want to solve this problem using Excel. There are two ways to approach it (easily). In this first method, we will look at the circular references method: (The second method is to use matrices)
Two substances, A and B, absorb light according to the Beer-Lambert law A = ecL where e is the extinction coefficient, c is the concentration of the absorbing substance and L is the path length (0.1 dm). If both species are in solution and the absorbance at 300 nm is measured to be 3.5 and the absorbance at 500 nm is 2.3, use simultaneous equations to calculate the concentrations of A and B in the mixed solution. The extinction coefficients, e are:
* At 300 nm, e(A) = 80; e(B) = 150 units
* At 500 nm, e(A) = 52, e(B) = 100 units.
This interactive presentation shows how simultaneous equations can be used in a variety of chemistry applications. The embedded flash videos require speakers/headphones. Along with the context-based examples, there is an overview of how to solve linear simultaneous equations. There is a quiz at the end for you to check your understanding. You can choose what elements to look at from the main menu. Click on the image to load the resource:
Additional Resources
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