The drug dobutamine (fw=301.38g/mol, c18h23no3c18h23n03) has a molar absorptivity of 703 at 262nm. one tablet is dissolved in water and diluted to a volume of 2l. if the solution exhibits an absorbance of 0.687 in the uv region at 262nm in a 1- cm cell, how many grams to dobutamine are contained in the tablet? a. 0.5277g b. 0.58889 c. 9.77x 10g d. 97.778ge. 9.7778g

0.589 g

Explanation:

The absorbance (A) of an analyte is related to its concentration (c) through the Beer-Lambert's law.

A = ε . l . c

where,

ε: molar absorptivity

l: optical path length

A = ε . l . c

0.687 = 703 M⁻¹.cm⁻¹ . 1 cm . c

c = 9.77 × 10⁻⁴ M

The molar mass is 301.38 g/mol and the volume of solution is 2 L. The mass of Dobutamine is:

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons