Question

A student's calibration curve for Blue #1 at 635 nm yields a straight line described by the equation y = 0.194 x + 0.025. If the measured absorbance for a solution of unknown concentration of Blue #1 is 0.293, what is the concentration of the Blue #1 solution? Provide your response to three digits after the decimal.

Answer 1

Answer:

1.38 M is the concentration of blue solution.

Explanation:

The equation of calibration curve:

$A=\epsilon \times l\times c$

where,

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

The graph between A and c will straight line with slope equal to prduct of $\epsilon and l$.

y = 0.194 x + 0.025.

A = 0.194 c+ 0.025

Given the absorbance of solution :

A = 0.293

So, concentration at this value of absorbance will be= c

$0.293=0.194 c+0.025$

$c=\frac{0.293-0.025}{0.194}=1.381\approx 1.38$

1.38 M is the concentration of blue solution.