During this lab our group successfully learned how to use and analyze samples using Spec 20. These tools are intuitive to use, however there are also some common mistakes that can be easily overlooked. Once the Spec 20 has had time to warm up, simply select the desired measurement (absorbance or transmittance percentage) along with the wavelength you will be measuring at 3. Once the appropriate parameters are selected, you need to insert a blank into the sample chamber to correctly zero the machine using the automatic zero function 3. It is essential to use an appropriate blank solution depending on the samples that will be measured. For example, when measuring food colors and aqueous solutions, water should be used as a blank. Once the machine has been correctly zeroed, the absorbance and transmittance of individual samples can be measured. Although the operation is quite simple, it is important to avoid simple mistakes. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay First, if you find that the transmittance is outside the 15% -85% range, you need to use a different wavelength. Data measured outside this range may not accurately display sample properties. Other common problems involve cuvettes. If a cuvette is not placed in the correct orientation, readings may be incorrect. To avoid this, always ensure that the triangle on the cuvette is facing the light source. Cuvettes should also be cleaned with chemical wipes to ensure there are no contaminants such as fingerprints or oils on the clear plastic, to ensure accurate readings. Using data collected from various samples analyzed with the Spec 20, we were able to determine the relationships between wavelength, transmittance, and absorbance. Transmittance refers to the percentage of light that passes through a sample from the source and is received by the detector compared to a blank, which has a transmittance of 100%. Absorbance refers to the amount of light that is absorbed by a sample compared to a blank, which has an absorbance of 0. After taking measurements of red and green food coloring samples at various wavelengths, we were capable of plotting both transmittance and absorbance on a graph. These graphs showed that absorbance was at its highest when transmittance was at its lowest and vice versa, giving them an inverse relationship. The red and green samples also had inverse relationships with each other. This relationship can be explained by looking at the color wheel. The color we see is the wavelength of the color that a sample transmits best. The complementary color, which is on the opposite side of the color wheel, is absorbed better by the swatch. For example, red and green are opposites on the color wheel. Red has the highest absorbance reading when analyzed at the green wavelength (~500 nm) and has the highest transmittance at the red wavelengths (~625 nm). Green has the opposite data values. The observed color of KMnO4 is purple, the compliment of which is yellow. As expected, we see that KMnO4 has the highest absorbance in the yellow wavelength (~550 nm). Another important attribute of absorbance is that it determines the analytical wavelength of a sample. This is found when the absorbance is at its maximum, which is when light of complementary wavelength is used and will provide the best wavelength for measuring the samples. We repeated these methods for.