1) 10 mL of a sample was diluted with 30 mL of solvent and the transmittance mea

Question

1) 10 mL of a sample was diluted with 30 mL of solvent and the transmittance measured to be 40% at 450 nm in a 2.25 cm cell. Using a molar absorptivity constant of 3285 L mol-1 cm-1, calculate the concentration of the sample in the original solution.

2)Two beams of radiation with wavelengths of 450 and 620 nm are both incident on a grating at 10°. Calculate the angle of separation of the first-order diffracted beams if the grating has 1150 grooves/mm.

3)The protons from a methyl group on an unknown compound has an NMR signal at 402 MHz. What is the wavelength and energy in kilojoules associated with the signal?

Explanation / Answer

ANSWER:

This is a set of three dfferent questions, So need to be send in three installments. Here we solve first problem. Thank You.

(1)

Absorbance (A) = log (Io/I) = ecl  --------------(1)

Io = intensity of incident light ; I = intensity of transmitted light (40%); e = absorptivity constant ; c = cconcentratio ;

l = length of solution

Or log (100/40) = 3285 Xc X 2.25cm

Or C = 0.38 /3285X2.25 = 5.14 X 10-5 M/L

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