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+) = ?
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?
𝐴 = 12.93 𝑀^−1 [𝐹𝑒^2+] + 0.0017
0.106 = 12.93(Fe^2+) + 0.0017
Solve for (Fe^2+) = ?
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!
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.
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.