When two or more substances are present in solution, the absorbance of the solut

Question

When two or more substances are present in solution, the absorbance of the solution s equal to the sum of the absorbances that would be measured on each substance if it were present alone. A solution containing NAD+ and NADH had an absorbance of 0.300 at 340 nm and 1.2 at 260 nm What were the concentrations of the two molar absorption coefficient, are Why are data at two wavelengths needed to solve this problem Ten grams of butter were saponified and the nonsaponifiable fraction extracted into 25 ml of chloroform. The optical density of the chloroform solution in a 1 cm cuvette was 0.53 at 328 nm and 0.48 at 458 nm. Calculate the carotene and vitamin A content of the butter. The extinction coefficients of carotene and vitamin A at the two wavelengths are given below: A solution containing two substances, A and B, has an absorbance in a 1 cm cuvette of 036 at 351 nm and 0.225 at 400 nm. The molar extinction coefficients of A and B at the two wavelengths are given below. Calculate the concentrations of A and B in the solution.

Explanation / Answer

There are multiple questions here . i am allowed to answer only 1 at a time. I will answer 1st question for you.Please ask other as different question

9.

let concentration of NAD+ be C1 and that of NADH be C2
at 340 nm, whole absorbence is due to NADH since extinction coefficient of NAD+ = 0
so,
0.3 = 6220* C2
C2=4.82*10^-5 M

Now use at 260 nm
18000 *C1 + 15000*C2 = 1.2
18000*C1 + 15000*(4.82*10^-5) = 1.2
C1=2.65*10^-5 M

Two wavelength are required because there are 2 unknown in the question C1 and C2 and hence we need atleast 2 equation to be formed.
Each wavelength's data forms 1 equation

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