Concentration of product(from Beer\'s law plot) How to do the graph for part B?

Question

Concentration of product(from Beer's law plot) How to do the graph for part B? plaees When taking the logarithm of a num after the decimal as signifi with a % transmitta ber, the resulting log should have as many cant figures in the original number. For example, a sample nce of 26.3 (3 significant figures) has an absorbance of A-2-log 26.3m2-1 log 26.3-2-1.420 -0.580 (3 places after the decimal) each solution has been calculated, the concentration of t . Gra Once the absorbance of colored iron-thiocyanate complex can be determined using a Beer's law plot the data below to construct a Beer's law plot for the iron-thiocyanate complexe s. U the graph to determine the concentration (in moles/liter) which corresponds to -thiocyar observed absorbance of each solution. This is the concentration of iron complex formed in each test tube after equilibrium has been reached. Data for the Beer's law plot follows. Graph the data following the general gr ing guidelines in the appendix and the specific guidelines in the experiment ent Spectrophotometric Determination of Dyes. This graph will be used to determin concentration of the iron-thiocyanate complex in each of the solutions you pre [iron(III)-thiocyanate complex] 3.088 × 10-5 M 6.176 ×10-5 M 9.264 × 10-5 M 1.235 × 10-4M 1.544 × 10-4M 1.853 × 10-4 M Absorbance 0.152 0.307 0.443 0.587 0.752 0.891 nce the initial concentrations and the exact volumes of Fes solution an ution are known, it is possible, using each of the three reactions propos ate the molarity (ie., equilibrium concentrations) of F() and SCN tion. Since the equilibrium concentrations of all three species appea nical equations are known, K can be calculated for all thre (ag) (aq) e postu eq hich occurred under these experimental conditions. ple calculation will beprovided for all three possile reactions f ple calculation will be provided for all three possible reactions fo e solution 1 was placed in a spectrophotometer, its % transmittan rbance calculated, and the corresponding concentration of irg

Explanation / Answer

First, you need to calculate the absorbance for all the tramitance you have in the data above, as you did part A but with every solution.

Once you have that, from the first chart you are putting in the first sheet, graph those values according to beer law which is:

A = EbC

Where A is absorbance, E is molar absorptivity, b is length of the cubet (usually 1 cm) and C is concentration.

So, you have to plot a graph of A vs C. Doing that with those data, we have the following results:

y = 4.6372x10-3 + 4786.85x ---> r2 = 0.9994

With this plot,all you have to do now, is replace the value of absorbance you got, and then solve for x (Concentration). For example, for the value you calculated in part A, the concentration would be:

0.09 = 4.6372x10-3 + 4786.85C

0.09 - 4.6372x10-3 = 4786.85C

C = 0.09 - 4.6372x10-3 / 4786.85

C = 1.783x10-5 M

Do this for all the values calculated of absorbance from your data, and you should get the concentration.

Hope this helps

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