Chapter 8, Problem 11P

What percent transmittance range and what absorbance range are considered to be the optimum working ranges for spectrochemical measurements?

The transmittance of a solution is found to be 35.0%. What is the transmittance if the solution is diluted in half?

The molar absorptivity for aqueous solutions of phenol at 211 nm is 6.17 × 103 L cm-1 mol-1. Calculate the permissible range of phenol concentrations if the transmittance is to be less than 85% and greater than 7% when the measurements are made in 1.00-cm cells.

A 7.25 x 10-5 M solution of potassium permanganate has a transmittance of 44.1% when measured in a 2.10-cm cell at a wavelength of 525 nm. Calculate (a)the absorbance of the solution, and (b) the molar absorptivity.

Which of the following is NOT a detector used with HPLC? evaporative light-scattering detector refractive index detector ultraviolet detector electrochemical detector thermal conductivity detector

A 1.2cm diameter glass cuvette is filled with a Cu(NH3)42+ solution that is deep blue. The cuvette is placed into a pre-blanked spectrophotometer. At 620nm, the transmittance is 23%.  If the solution has molarity = 0.0133 M and path length of light through the solution = 1.2 cm, what is the value of molar absorptivity at 620 nm?

7 A rectangular surface of 4 m2 was exposed to solar radiation of 1400 W/m2. The temperature of the surface was maintained at 500K. The spectral absorptivity of the surface is given as 0 for 0> λ (μm) < 0.5, 0.8 for 0.5> λ (μm)< 1, 0 for 1< λ (μm) < 2, and 0.9 for λ (μm)>2. Assuming the surface is diffuse and the sun temperature is 5800K, calculate the absorbed irradiation, radiosity, and net radiation heat transfer from the surface.

You are given two containers, one with 3.00 mg Mn 2+ and one with an unknown amount of Mn 2+ .You oxidize the Mn 2+ to the purple permanganate ion (MnO 4 - ) and dilute the solutions to 250.0 mLs.The solution containing the 3.00 mg Mn is used to prepare a third solution containing 1.50 mg Mn.The transmittances of the solutions are measured at 530 nm using a dilapidated Spectronic 20. Fromthe data below, calculate the amount of Mn in the unknown. For a linear curve, consider y=kx+b Mn (mg)        %T3.00               30.81.50               55.2Unknown       37.4

What absorbance corresponds to 1% transmittance? To 50% transmittance?