I'm trying to do a lab, and I need to find the concentration of FeSCN+2 in five solutions based the calibration curve and the absorption. I have a calibration curve, the number of mLs and initial moles of Fe+3 and SCN-, the transmittances, the absorbencies, and the equation. I've tried my textbook, but it doesn't have the topic.
If you have the calibration curve, I assume it is A vs concentration. Choose your A values for the unknown, read the concn from the graph. I don't know how your graph is calibrated; therefore, I don't know the concn units, but you will need to convert that concn you find to the initial values of the unknowns. You know the dilutions you made.I'm sorry to be so vague but you don't have any numbers for me to be more helpful.
To find the concentration of FeSCN+2 in the five solutions based on the calibration curve and absorption data, you can follow these steps:
Step 1: Understand the equation and the calibration curve
Make sure you are familiar with the equation that relates the absorbance (A) to the concentration of FeSCN+2 in the solution:
A = εbc
Where:
A = absorbance
ε = molar absorptivity constant (which should be provided)
b = path length of the cuvette (which should be provided)
c = concentration of FeSCN+2 in moles per liter (M)
Also, check if your calibration curve is linear. If it is, you can use the equation of a straight line (y = mx + b) to relate the absorbance values to the concentration of FeSCN+2.
Step 2: Determine the concentration of FeSCN+2 using absorbance data
For each of the five solutions, you need the absorbance value at a specific wavelength. Plug this absorbance value into the equation from step 1 and solve for the concentration (c) of FeSCN+2.
c = A / (εb)
Step 3: Convert molar concentration to mLs and initial moles
Once you have the concentration (c) of FeSCN+2 in moles per liter (M), you can convert it to mLs and initial moles using the given information.
If you know the volume (V) of the solution in liters:
moles = c * V
Alternatively, if you know the initial moles (n0) and the initial volume (V0) that were mixed to obtain the solution:
final moles = n0 / V0 * V
Repeat step 2 and 3 for each of the five solutions, using their respective absorbance values and the given information.
Note: Make sure you are using the correct units and that your calculations are consistent throughout the lab. Also, double-check your results and make any necessary adjustments based on the specific requirements of your lab.