Ergosterol, a precursor of vitamin d, has δmax = 282 nm and molar absorptivity ε = 11,900 m-1cm-1. what is the concentration of ergosterol in a solution whose absorbance a = 0.43 with a sample pathlength l = 1.00 cm.?

3.6 × 10⁻⁵ M

Explanation:

Ergosterol has a maximum absorbance at λ = 282 nm. The absorbance of an analyte is related to its concentration through the Beer-Lambert's law.

A = ε × l × c

where,

A: absorbance

ε: molar absorptivity

l: optical path length

c; molar concentration

c = A / ε × l = 0.43 / (11,900 M⁻¹cm⁻¹) × 1.00 cm = 3.6 × 10⁻⁵ M

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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