Table of contents

1. Chemical Measurements1h 50m
2. Tools of the Trade1h 17m
3. Experimental Error1h 52m
4 & 5. Statistics, Quality Assurance and Calibration Methods1h 57m
6. Chemical Equilibrium3h 41m
7. Activity and the Systematic Treatment of Equilibrium1h 0m
8. Monoprotic Acid-Base Equilibria1h 53m
9. Polyprotic Acid-Base Equilibria2h 17m
10. Acid-Base Titrations2h 37m
11. EDTA Titrations1h 34m
12. Advanced Topics in Equilibrium1h 16m
13. Fundamentals of Electrochemistry2h 19m
14. Electrodes and Potentiometry41m
15. Redox Titrations1h 14m
16. Electroanalytical Techniques57m
17. Fundamentals of Spectrophotometry50m

17. Fundamentals of Spectrophotometry

Measuring Absorbance

Analytical Chemistry

17. Fundamentals of Spectrophotometry

Measuring Absorbance

Previous problem

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Multiple Choice

When analyzing an absorbance spectrum, which approach is most appropriate for identifying compounds present in a mixture?

Use the total area under the absorbance curve without considering peak locations.

Compare the wavelengths of 1-2 key absorbance peaks to known reference spectra.

Ignore peak positions and focus solely on the baseline of the spectrum.

Only consider the intensity of the highest absorbance peak.

Previous problem

Verified step by step guidance

Understand the problem: The question is asking about the most appropriate approach for identifying compounds in a mixture using an absorbance spectrum. Absorbance spectra are used in analytical chemistry to identify and quantify compounds based on their interaction with light at specific wavelengths.

Step 1: Recall the principle of absorbance spectroscopy. Each compound has a unique absorbance spectrum, which is characterized by specific wavelengths where it absorbs light. These wavelengths correspond to electronic transitions in the molecule and are often referred to as 'key absorbance peaks.'

Step 2: Evaluate the options provided. The first option suggests using the total area under the absorbance curve, but this does not provide specific information about the identity of the compound, as it does not consider the unique wavelengths of absorbance. The second option suggests comparing the wavelengths of 1-2 key absorbance peaks to known reference spectra, which is a standard and effective method for identifying compounds. The third option suggests ignoring peak positions and focusing on the baseline, which is not scientifically valid for identification. The fourth option suggests only considering the intensity of the highest absorbance peak, but this alone does not provide enough information for identification.

Step 3: Focus on the correct approach. Comparing the wavelengths of 1-2 key absorbance peaks to known reference spectra is the most appropriate method because it leverages the unique spectral fingerprint of each compound. This method allows for accurate identification by matching the observed peaks to those in a database or reference material.

Step 4: Conclude that the correct answer is to compare the wavelengths of 1-2 key absorbance peaks to known reference spectra, as this method is based on the fundamental principles of absorbance spectroscopy and provides reliable identification of compounds in a mixture.