What wavelength is most suitable for quantitative analyses for an analyte exhibiting the UV-Vis Spectrum shown below (which has an interfering analyte with the spectrum shown in a dashed line)? Explain why? 1.0r B 0.75 0.50- E 0.25 350 400 450 500 550 600 650 Wavelength, nm Figure 3-19 Choice of experimental wavelength. Solid line: measured species. Dashed line: interfering species. See text for details. Absorbance

Explain why is absorption used for studying the dyes, while fluorescence is used for studying the quantum dots?

A mixture of species of A and B is injected into a liquid chromatographic column with length of 20.0 cm. The obtained separation results are listed as follows: Species Retention time (min) Peak Width at Base (min) Non-retained 3.0 A 5.2 0.48 В 5.9 0.56 From the data, the calculated resolution Rs is smaller than 1.5 for A and B when the column length is 20.0 cm, which indicates that A and B are not separate completely. What is the new column length (unit: cm) necessary to separate the A and B species with a good resolution Rs = 1.5? Please keep your answer to one decimal place.

The image shows a whole body bone scan using MDP (mono-diphosphonate) labelled with technetium-99m. • Patient is injected with 600 MBq of Tc-99 MDP • Technetium-99m is a pure gamma emitter, with physical half life of 6 hours. a) Use the data to explain why technetium 99-m is a suitable radionuclide (AC 3.1)

Besides 1H NMR, FT-IR, melting point, data for refractive index, what other information could you obtain for your compound to assess its’ purity and confirm its’ structure? How would this additional data contribute to your conclusion about the structure of the unknown compound?

How are these equal? How would I know to match these? 25 km = 25,000 m 2.5 cm = 2.5 × 104 μm 0.25 m = 2.5 × 108 nm 2.5 mm = 2.5 × 10-6 km