Question

the complex that is formed between gallium (iii) and 8-hydroxyquinoline has an absorption maximum of 634nm. a 961mm solution of the complex has a transmittance of 16.4% when measured in a 1.00-cm cell at this wavelength. calculate the molar absorptivity(m-1cm-1) of the complex.

Answer 1

To find the molar absorptivity of the gallium (III)-8-hydroxyquinoline complex at 634 nm, first the absorbance is calculated from the given transmittance of 16.4%.

Step-by-step explanation:

The transmittance (T) is the ratio of light intensity that passes through the sample (I) to the initial light intensity (I0), and it is expressed as a percentage. Absorbance (A) is calculated using the formula A = -log10(T). In this case, the transmittance (T) of the gallium (III)-8-hydroxyquinoline complex is 16.4%, or 0.164 when expressed as a decimal.

The equation A = -log10(T) gives us:A = -log10(0.164) = 0.785. Using the absorbance and the provided path length of 1.00 cm, with the concentration of the solution being 961µM or 9.61 x 10-4 M, we can solve for ε as follows: ε = A / (c * l) = 0.785 / (9.61 x 10-4 M * 1.00 cm) ≈ 816.858 M-1cm-1.

The molar absorptivity of the gallium (III)-8-hydroxyquinoline complex at 634 nm is therefore approximately 817 M-1cm-1.