Would the following errors cause an increase or decrease in absorbance and % Transmittance?
insoluble particles were accidentally pipetted into the cuvette with the solution
the cuvette was wet and not prerinsed with the solution.
fingerprints were not wiped off the outside of the cuvette.
the wavelength was changed from maxto max+10 nm.
Most of these are common sense if you think about them in terms of what you did in the lab. Please tell us what you think the answers are and why you think that and we shall try to critique your thoughts.
A increase and T decrease
1. decrease absorbance and decrease % transmittance
2. decrease absorbance and increase % transmittance
3. increase absorbance and decrease % transmittance
4. decrease absorbance and increase % transmittance
1.) Increase absorbance & decrease % transmittance
all the other answer above are correct
Based on the given scenarios, here are the expected effects on absorbance and % transmittance:
1. Insoluble particles were accidentally pipetted into the cuvette with the solution:
In this case, the presence of insoluble particles would scatter light, causing an increase in absorbance and a decrease in % transmittance. The particles would interfere with the passage of light through the solution, resulting in less light reaching the detector and thus lower transmittance.
2. The cuvette was wet and not prerinsed with the solution:
If the cuvette is wet with water or any other liquid that is different from the solution being tested, it can affect the accuracy of the measurements. Water may have different optical properties compared to the solution, resulting in altered absorbance and % transmittance values. However, it is challenging to determine whether this would increase or decrease absorbance and % transmittance without more specific information.
3. Fingerprints were not wiped off the outside of the cuvette:
Fingerprints on the outside surface of the cuvette do not directly affect the measurement of absorbance and % transmittance. The light beam passes through the clear and transparent walls of the cuvette, and any impurities or contaminants on the outside would not significantly impact the passage of light through the solution inside.
4. The wavelength was changed from max to max+10 nm:
The absorbance of a solution can be sensitive to the wavelength of light used. If the wavelength is changed from the maximum absorbance wavelength (max) of the substance to a slightly higher wavelength (max+10 nm), it is likely that the absorbance will decrease. This occurs because the solution may absorb less of the light at a slightly different wavelength, leading to a lower absorbance value. However, without knowing the specific properties of the substance being tested, it is challenging to determine the precise effect on % transmittance.
Overall, only scenarios 1 (insoluble particles) and 4 (wavelength change) are likely to have noticeable effects on absorbance and % transmittance.
If insoluble particles were accidentally pipetted into the cuvette with the solution, this would generally cause an increase in absorbance and a decrease in percent transmittance. The presence of the particles will scatter light, leading to reduced transmission of light through the solution and increased absorbance.
If the cuvette was wet and not prerinsed with the solution, this could also cause an increase in absorbance and a decrease in percent transmittance. Water or other liquids on the cuvette surface can interfere with the proper transmission of light through the solution, contributing to higher absorbance values and lower percent transmittance.
If fingerprints were not wiped off the outside of the cuvette, this typically would not have a significant effect on absorbance or percent transmittance. As long as the inside of the cuvette remains clean and clear, the presence of fingerprints on the outside should not significantly impact the measurements.
Finally, if the wavelength was changed from max to max+10 nm, this could potentially result in a change in absorbance and percent transmittance. Absorbance and transmittance are wavelength-dependent, with different substances having specific absorption maxima. Changing the wavelength used for measurement could result in different levels of absorption and transmission, potentially leading to differences in absorbance and percent transmittance values. However, the specific effect would depend on the molecule being analyzed and its absorption characteristics.
It's important to note that these are general assumptions based on common laboratory experiences, but the actual impact of these errors may vary depending on the specific experimental setup and the properties of the substances involved.