Question

In a hurry to complete the experiment, Joseph failed to calibrate the spectrophotometer. As a result, all absorbance values for the standard solutions that are measured and recorded are too high. How will this affect the following for the Test Solutions?

Answer 1

$\boxed{{\text{Incorrect results}}}$ will be observed for test solutions if calibration of spectrophotometer is not done.

Further explanation:

Spectrophotometry

It is a technique that is used to measure the absorbance of light as a measure of the intensity of light when light passes through the sample of the solution. The optical instrument used for such purpose is a spectrophotometer.

Lambert-Beer’s Law

This law relates to the absorbance of the species to its concentration and the optical path length through the sample. The mathematical expression for Lambert-Beer’s law is,

$\boxed{A = \varepsilon lc}$  

Here,

A is the absorbance of the species.

$\varepsilon$ is the molar absorptivity of the species.

l is the optical path length.

c is the concentration of species.

While using a spectrophotometer, calibration is an essential step in determining the absorbance of the sample. This done by using a blank solution (standard solution) and taking its absorbance value as a reference for other solutions. But if the equipment is not calibrated before measuring the absorbance for other solutions, the results will be incorrect.

In the given experiment, the absorbance values of standard solutions are recorded very high. This will lead to incorrect values of absorbance for test solutions. This is because the absorbance of the standard solution is to be used as a reference for the test solutions.

Learn more:

1. Classify the transitions as absorption or emission of light: brainly.com/question/1594022

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Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Beer-Lambert Law

Keywords: absorbance, Lambert-Beer law, calibration, standard solutions, test solutions, blank solution, spectrophotometry, spectrophotometer.

Answer 2

Joseph will not get the correct results for his samples. The spectophotometer will measure wrong absorbance values for the sample. It is highly advised to callibrate the instrument by first setting the absorbance of the solvent to zero. After it is done, only then one must determine the absorbance of the test solutions.