Reflection And Discussion On Absorption Spectra

3ml of sample was taken first flask at 4 minutes and added to the appropriate tube of sodium hydroxide, from the second flask at 4.5 minute and so on, each flask was sampled at 30 second intervals. The sampling was then repeated starting at 8,12,16 minutes. The final sample from the last flask was taken at 18.5 minutes. Once the sampling was completed, measurements of absorbance were obtained for solution in each tube at 405 nm.

Magnesium ribbon was reacted with Hydrochloric acid in three different experiments to determine the charge on a metal ion. After running multiple tests in the three different procedures, the Crystallization method proved to be the best method for determining the charge of the metal ion by using mole to mole ratio.

The experiment was successfully achieved the purpose of this lab: to determine the concentration of Mg2+ using compleximetric tritation. During the experiment, the color in the unknown solution was successfully changed

The Beers Law calibration experiment used many concentrations of crystal violet solutions. Each of these solutions were test and analyzed in order to determine the absorbance of each concentration The results were than graphed and produced a slope of 1.00E05 with an intercept of -2.21E-02.

The wavelength of the light should be a different color from the solution’s color. This is because if the color of the wavelength of the light is the same color as the solution’s color, then the color would not be absorbed. The only way that a solution can absorb a color is if the color of the light’s wavelength is its complementary (opposite) color. The color of the light chosen for this experiment was blue because the wavelength was set to 430nm, which corresponds to blue's wavelength. The color of the FeSCN2+ complex ion is blood-red.

The goal of this experiment is to prepare a photosensitive solution and explore its properties. While analyzing the solution, one will learn how to successfully handle these sensitive chemicals and then establish its properties via spectrophotometry.

Spectroscopy Spectroscopy is the study of energy levels in atoms or molecules, using absorbed or emitted electromagnetic radiation. There are many categories of spectroscopy eg. Atomic and infrared spectroscopy, which have numerous uses and are essential in the world of science. When investigating spectroscopy four parameters have to be considered; spectral range, spectral bandwidth, spectral sampling and signal-to-noise ratio, as they describe the capability of a spectrometer. In the world of spectroscopy there are many employment and educational opportunities as the interest in spectroscopy and related products is increasing.

AAS has contributed to the understanding of elements having different absorption emission spectra due to their difference in energy levels. In the absorption spectrum, the absorbed light are shown as black gaps. As the number of electrons increase, the number of spectral lines also increase. Hence, by measuring the absorption of light, the concentration of the element within a sample can be determined. By knowing the concentrations of an element, scientists are now aware that even the smallest amount can make a significant impact towards the biological system. Therefore, scientists have brainstormed ways to monitor the use of chemicals in the

A Mohr pipette allowed for the accurate measuring of a standard solution, by recording the final and initial pipette readings of 0.200 M Fe(NO3)3 and 0.00200 M KSCN. With Le Chatlier’s principle in mind, an excess of 0.200 M Fe(NO3)3 was used rather than 0.00200 M as a flooding technique to keep Fe(NO3)3 constant throughout the reaction and favor the products. To determine the equilibrium solutions, four 50 ml beakers were obtained by recording their final, initial, and total volume dispensed. Beaker 1 consisted of 5 ml Fe(NO3)3, 2 ml KSCN, and 3 ml H2O. Beaker 2 contained 5 ml Fe(NO3)3, 3 ml KSCN, and 2 ml H2O. Beaker 3 consisted of 5 ml Fe(NO3)3, 4 ml KSCN, and l ml H2O. Lastly, beaker 4 contained 5 ml Fe(NO3)3 and 5 ml KSCN. Next, the absorbance values were calculated by placing each solution into a 470 nm colorimeter, then using Logger Pro to determine the absorbance for each solution when given the concentration values. As seen in table 3, the absorbance value for the standard solution was 0.818 with a [Fe(SCN)2+] concentration of 2.00  10-4 M. To reduce error, Mohr pipette readings were recorded to two decimal places and data was not recorded on the meniscus of the line. This allowed for a higher quality of recordings and the avoidance of biased

In this experiment, two reactions were run to determine the molar absorptivity and the equilibrium constant of FeSCN2+. The main principles used in this lab are equilibrium, LeChatlier’s Principle, Beer’s Law and Spectrocopy. The first reaction was run to completion using LeChatier’s Principle and the second reaction was run to equilibrium. A spectrophotometer was used to measure absorbances. Using a graph of absorbance versus concentration of FeSCN2+ was used to determine that the molar absorptivity constant was 3670. Beer’s Law was used to determine that the average equilibrium constant was 33.1793.

The purpose of this experiment was to determine the pKa of the bromothymol blue (indicator) through absorption spectroscopy. Bromothymol blue being a monoprotic acid base indicator, displays different colors at different pH because of the differences in the ratio of the conjugated acid and base form. The fraction of conjugate acid and base was interpolated for the solutions through the acquired absorbance spectrum of the bromothymol blue at various pH. The rearranged form of Henderson Hasselbalch equation was graphed as a function of pH to determine the pKa of the indicator.

Evening help sessions: Wednesdays 5:00-6:30 p.m. in Hancock 209 beginning on September 4. ON WEEKS WHEN THERE IS A TUESDAY TEST, THE HELP SESSION WILL BE ON MONDAY INSTEAD OF WEDNESDAY AND WILL BE HELD FROM 7:00-8:30 IN ENGEL 223. Attendance at Help Sessions is entirely optional but can be helpful.

The highly conjugated system of the cyanine dyes makes it a very good compound in the development of more efficient solar cells. In this experiment, the maximum wavelength was measured for nine dyes using a UV-Vis spectrum. The result that were obtained agreed with Kuhn’s model for the less polarizable end groups such as 3,3 '-diethyloxadicarbocyanine and 3,3 '-diethyloxatricarbocyanine. That suggested that these two compounds were not as easy to polarize compared to the rest of the dyes. The rest of the dyes required the use of the empirical parameter α to provide more reliable predictions of the wavelengths. This was due to the highly polarized ends of the dyes which needed the adjustment of the parameter to get more accurate results. The series with the higher polarizable end groups’ absorbed higher wavelength light than the less polarized groups. This supported the idea of the one-dimensional box. Also, higher wavelength was determined to be associated with longer conjugated carbon methine chains between the Nitrogen atoms. Kuhn’s free electron model was very reliable for this system.

I am currently a junior Applied Math major at Marist and plan on declaring a biology minor. In order to satisfy the requirements before graduation, it would be most ideal for me take one the three required upper level bio electives during each of my three semesters remaining at Marist. I am currently in General Chemistry I, so I would need to be enrolled in General Chemistry II next semester as well. My current issue is that Gen Chem II is a prerequisite for nearly all the possible upper level electives. So, I was wondering if we could meet sometime to discuss the option of getting a corequisite waiver, if even at all possible. Please let me know if you have any available time this week or early next week to meet with me, as

Before any calculations, the spectra from the HCl solution and NaOH solution was verified to make sure that the wavelength at which the deprotonated form of 2-naphthol absorbs at 345 nm and that protonated form does not absorb significantly at the same wavelength. All the spectra in Figure 1 were baseline-corrected using the HCl solution spectrum, shown in Figure 2, and the NaOH solution spectrum was used to determine Amax at 345 nm.