The equation for a normal calibration curve for the detection of
iron(II) is determined experimentally to be
𝐴 = 12.93 𝑀^−1 [𝐹𝑒^2+] + 0.0017
Analysis of a sample with unknown concentration gives an
absorbance reading of 0.106. What is the concentration of iron(II) in
the unknown?
Plug in the numbers and solve the equation.
𝐴 = 12.93 𝑀^−1 [𝐹𝑒^2+] + 0.0017
0.106 = 12.93(Fe^2+) + 0.0017
Solve for (Fe^2+) = ?
Well, well, what do we have here? A mysterious unknown concentration of iron(II)? Let's solve this case together, my curious friend!
According to the given calibration curve equation, we have A = 12.93 M^(-1)[Fe^2+] + 0.0017. But wait, we have a value for A, which is 0.106. So, let's plug that in and solve for the concentration [Fe^2+].
0.106 = 12.93 M^(-1)[Fe^2+] + 0.0017
Now, we'll subtract 0.0017 from both sides to isolate the term with [Fe^2+].
0.106 - 0.0017 = 12.93 M^(-1)[Fe^2+]
Simplifying:
0.1043 = 12.93 M^(-1)[Fe^2+]
To find [Fe^2+], we can divide both sides by 12.93 M^(-1):
0.1043 / 12.93 M^(-1) = [Fe^2+]
After some number-crunching:
[Fe^2+] ≈ 0.00806 M
Voila! The concentration of iron(II) in the unknown sample is approximately 0.00806 M. Mystery solved!
To find the concentration of iron(II) in the unknown sample, we can rearrange the equation for the calibration curve:
A = 12.93 [Fe^2+] + 0.0017
Given that the absorbance reading is 0.106, we can substitute this value for A:
0.106 = 12.93 [Fe^2+] + 0.0017
Now, let's solve this equation for [Fe^2+].
Subtracting 0.0017 from both sides of the equation:
0.106 - 0.0017 = 12.93 [Fe^2+]
Simplifying:
0.1043 = 12.93 [Fe^2+]
Dividing both sides of the equation by 12.93:
0.1043 / 12.93 = [Fe^2+]
Calculating the value:
[Fe^2+] ≈ 0.00805 M
Therefore, the concentration of iron(II) in the unknown sample is approximately 0.00805 M.
To find the concentration of iron(II) in the unknown sample, we can use the calibration curve equation and substitute the given absorbance value.
The equation for the calibration curve is:
A = 12.93 M^−1 [Fe^2+] + 0.0017
Here, A represents the absorbance reading and [Fe^2+] represents the concentration of iron(II).
Given absorbance reading:
A = 0.106
Substituting the absorbance value into the equation, we get:
0.106 = 12.93 M^−1 [Fe^2+] + 0.0017
Now, we can rearrange the equation to isolate [Fe^2+]:
12.93 M^−1 [Fe^2+] = 0.106 - 0.0017
Simplifying further:
12.93 M^−1 [Fe^2+] = 0.1043
To find the concentration of iron(II), divide both sides of the equation by 12.93 M^−1:
[Fe^2+] = 0.1043 / 12.93 M^−1
Evaluating the expression:
[Fe^2+] = 0.00805 M
Therefore, the concentration of iron(II) in the unknown sample is 0.00805 M.