Question

A light absorbing chemical has a molar absorptivity constant of 487 L/mol*cm. For a system with a 1.00 cm path length, what chemical concentration would result in a recorded % transmittance of 31.6?a. None of these b. 974 M c. 0.000649 M d. 0.00103 M e. 0.0649 M

Answer 1

The right answer is Option d (0.00103 M).

Step-by-step explanation:

The given values are:

T = 31.6

e = 487 L mol cm

length, l = 1 cm

As we know,

Absorbance,

`A=2-log_(10)(percent \ T)`

`A=2-log_(10)(31.6)`

`A=0.5003`

By using the Beer's law, we get

⇒
`A=ecl`

⇒
`c=(A)/(el)`

On substituting the values, we get

⇒
`=(0.5003)/(487* 1)`

⇒
`=0.001027 \ (mol)/(L)`

⇒
`=0.00103 \ M`