Question

The molar absorptivity of a compound at 500 nm wavelength is 252 M-1cm-1. Suppose one prepares a solution by dissolving 0.00140 moles of a solute in enough water to make a 500.0 mL solution. What would be the absorbance in a 3 .00 mm pathlength cell?

Answer 1

Answer:

The absorbance of the solution is 0.21168.

Explanation:

Given that,

Wavelength = 500 nm

Molar absorptivity = 252 M⁻¹ cm⁻¹

Number of moles = 0.00140

Volume of solution = 500.0 mL

Length = 3.00 mm

We need to calculate the molar concentration

Using formula of the molar concentration

$C=\dfrac{N}{V}$

Where, N = number of moles

V = volume

Put the value into the formula

$C=\dfrac{0.00140}{0.5000}$

$C=0.0028\ M$

We need to calculate the absorbance of the solution

Using formula of absorbance

$A=\epsilon C l$

Put the value into the formula

$A=252\times0.0028\times0.300$

$A=0.21168$

Hence, The absorbance of the solution is 0.21168.