Scientific Explanation Lab Report

Make sure to use the same type of cuvette to keep the width consistent and to prevent any experimental error from arising. Obtain 5 of the same type of cuvettes and pre-rinse them thoroughly. Label them numbers one through five in increasing molarity. Then, fill each of the cuvettes with one of the five solutions you created back in Part A. We will first examine the solution that exhibits the highest concentration or molarity. Make sure to wipe the outside of the cuvette with a Kimwipe before placing into the SpectroVis Plus device. Observe the graph that is generated and make sure to take note where the maximum absorbance takes place.

The concentrations and absorbances of the red and blue dyes were used to find the concentration of the purple dyes. From the graph of the blue dye, the linear equation for absorbance was y = mx + b. From that formula came the equation y = 7.915 x 104 (x) + 0.02489, where y represents absorbance, m is slope, x is concentration/molarity, and b is the constant/y-intercept. The same set up was performed for the red dye, but the equation produced was y = 1.045 x 104 (x) +.001298. The equations found when graphing absorbance vs. concentration were used to find the concentration of the purple dyes. The absorbance for purple dye 3 on the red wavelength of 470 nm equaled 0.149 and 0.818 for the blue wavelength of 635 nm. For purple dye 1

Diluted 20 mL of the blue dye with 5 mL of DI water and placed the diluted solution into the spectrometer. Recorded the results of the absorbance of the diluted concentration of the blue dye by again, looking at the peaks on the spectroscopy. Repeated the dilution four more times with the blue dye, and recorded the absorbance of the subsequent concentrations of blue dye. Repeated the same steps as the blue dye again, except for the red dye after the blue dye trials were

Discussion of Results and Scientific Explanations: The goal of this laboratory was learn how to use the Spectrophotometer to analyze the phosphate content in colas. This is important because the consumers believe that the buffering capacity of phosphate within the colas will settle their upset stomachs.  A spectrophotometer, or Spec 20, measures how much a chemical substance absorbs and transmits. The next goal is to determine the relationship between absorbance and transmittance.  Transmittance is a measurement of the amount of light that passes through a substance.

For this experiment, the amounts of Red 40 and Blue 1 were quantified in six different Kool-Aid samples through the use of a spectrophotometer. This was completing by performing serial dilutions on both dyes, Red 40 and Blue 1, and then creating calibration curves for each of the six samples. The absorbance and maximum wavelength values were obtained from the spectrophotometer for each individual drink sample. Beer’s Law was used to discover the concentration of

The values of color absorbance are effective because color absorbance has a linear relationship with concentration values, which in turn, allows us to easily find concentration values for many solutions. Beer’s law describes this phenomenon since the absorbance is directly proportional to concentration. We observed that as the color absorbance increased, the concentration of the FeSCN2+ complex ion increased. This is because as the FeSCN2+ concentration increases, the blood-red color becomes darker due to more presence of the blood-red FeSCN2+ ion. Therefore, the color absorbance increases because there is more blue color absorbed by the darker red color. We then graphed the absorbance and concentration values and created a line of best fit. Using the line of best fit, we were able to predict the equilibrium concentrations of the FeSCN2+ solutions and find the change required to reach equilibrium. Since we already knew the initial concentration of FeSCN2+ and since we already found the equilibrium concentration of FeSCN2+, we can calculate the change in equilibrium. Using this data, we were able to calculate the equilibrium concentration of all of the species in this lab, since we already knew the change from the initial concentration to the equilibrium change. Q is less than K because there was no initial concentration of FeSCN2+, but after the system reached

The dyes in the laboratory experiment are made of numerous colors, mainly red and blue, the spectra from each of the dyes corresponded to the wavelengths obtained from each of dye i.e. 620 nm for red and 450 nm for blue.

In part two of the experiment, the spectrophotometer was turned on and set to read the % transmittance of 600 nm wavelength light. 6 cuvettes were then obtained and labeled B-1 and B-2 (to

The tube was shaken up until it become uniformly green and the spectrophotometer was set at zero using this tube. Tube #1 acted as a control for reduction of DCIP in absence of CMS. 0.5 ml of DCIP and 1.5 ml of water was added to the tube and it was shaken up until it was well mixed. The absorbance was taken at that time. After that, with the light off, the tube was placed on the slanted portion of the foam pad in the light box. The light was turned on again and the tube was exposed to light for 1 minute.

concentration, record the absorbance readings at a fixed wavelength, and plot the absorbance vs. concentration data. The wavelength of 520 nm was selected for experiment Part

In this lab the concentration of allura red will be found. The vernier colorimeter will be used for this lab. Stock solution of a known concentration will be made, the absorption of each will be measured, when absorbance vs. concentration is plotted it should result in linear plot, which is called a calibration plot. The plot comes from the beer-lambert law, which is A=Kc. Measuring the concentration of allura red can be found by measuring the absorption of light through the solution. Cuvettes will be used in this lab to find concentration each solution; they will be placed in the cuvette then put into colorimeter to find absorption. Once that is complete data pairs will be examined by making a graph of absorbance vs. concentration with a

The ending result of this experiment confirms that as five test tubes are lined up with the varying level of absorbance, different results in the level of absorbance will appear as well, this is visible in above table. Thus, this is due to the varying amount of water in the solution. The blank sample had a 0.30 in its level of absorbance.

Then measured the absorbance of blue fractions that are within 5% of before and after the absorbance of the darkest blue one. Repeated the same steps with the yellow fractions, measured them at 440nm.

The overall purpose of the lab is to have the students practice designing an experiment, gathering data, and then analyzing that data to form a conclusion using the scientific method. It also served to understand key terms such as hypothesis, dependent variable, and independent variable. The specific objective of this lab is to determine whether certain human body parts experience allometric or isometric growth. Allometric growth defines when certain parts of an organism grow at unequal rates in comparison to its whole, while isometric growth is when all parts of an organism grow at the same rate in comparison to the entire organism. The specific purpose of the lab is to determine whether or not specific human body parts experience allometric or isometric growth by comparing the ratios of height to two specific body parts, in the students’ case the right hand length and head circumference, in students and newborns. The students formulated the tentative answer that if a team of four compared their height to right hand length ratio, as well as, their height to head circumference ratio, to those of a newborn’s, then the students will discover that the right hand and head experience allometric growth in humans.

Some fibers absorb a little more blue than red and less green than yellow and others just the opposite. Consequently, the hue and tone of the light varies from meter to meter, in some cases very apparently. This phenomenon is referred to as selective spectral absorption.