# Solve Beer's Law Problem: Fe2+ Spectral Analysis

• Lancelot59
In summary, the conversation involves solving a problem related to Beer's Law and spectral analysis of a sample containing Fe2+ ions. The absorbance, mass sample, slope, and y-intercept are given, and the individual uses the equation y=mx+b to obtain a concentration of 3.1662x10-5M. The question then arises about finding the mass of iron in the original sample, and it is determined that all dilutions need to be accounted for in the calculation. It is suggested to use the final volume of the sample to simplify the process.
Lancelot59
I'm having an issue solving a problem involving beers law. It's the specral analysis of a sample containing Fe2+ ions.

Absorbancy: 0.393
Mass Sample: 0.1950
Slope: 0.2200 mg Fe2+/L
y Intercept=0.004

So I worked y=mx+b to work out that there was 1.76818182 mg Fe+2/L

Then I converted to grams, and from there I divided by the molar mass of iron to get a concentration of 3.1662x10-5M.

I need to find the mass of Iron in the original sample. The lab procedure lists a whole bunch of dilutions that occur along the way. Adding some 1,10-phenanthroline, sodium acetate, and some other things. Do I really need to work all the dilutions back, or is there another way to get the answer?

You need to account for all dilutions. That is - could be you don't have to calculate every single one separately, if you are given information that allows calculation of the final volume of the sample, you can use it and treat whole process of diluting as a one step.

--

That works. Thanks.

## 1. What is Beer's Law and how does it relate to Fe2+ spectral analysis?

Beer's Law is a scientific principle that relates the concentration of a substance in a solution to the amount of light it absorbs. In the context of Fe2+ spectral analysis, this law is used to quantitatively determine the concentration of Fe2+ ions in a solution by measuring the absorbance of light at a specific wavelength.

## 2. How do you set up a Beer's Law problem for Fe2+ spectral analysis?

To set up a Beer's Law problem for Fe2+ spectral analysis, you will need to know the molar absorptivity coefficient, the path length of the solution, and the absorbance of the solution at a specific wavelength. These values can then be used in the Beer's Law equation (A=εbc) to calculate the concentration of Fe2+ ions in the solution.

## 3. What is the significance of the molar absorptivity coefficient in Fe2+ spectral analysis?

The molar absorptivity coefficient, also known as the molar extinction coefficient, is a measure of how strongly a substance absorbs light at a specific wavelength. In Fe2+ spectral analysis, this value is used to convert the absorbance of the solution into a concentration of Fe2+ ions.

## 4. How does the path length of the solution affect the accuracy of Fe2+ spectral analysis?

The path length of the solution, which is the length that light travels through the solution, is an important factor in Fe2+ spectral analysis. A longer path length will result in a higher absorbance, which can improve the accuracy of the analysis. However, it is important to keep the path length consistent in order to maintain accuracy.

## 5. What are some potential sources of error in Fe2+ spectral analysis?

Some potential sources of error in Fe2+ spectral analysis include instrumental errors, such as incorrect calibration or variations in light intensity, and human errors, such as inaccurate measurement of solution volume or not following proper experimental procedures. Other factors, such as the presence of interfering substances or the stability of the Fe2+ ions in solution, can also affect the accuracy of the analysis.

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