Determining How Much Acid Was In A Sample Of Coca-Cola

1. Fill in the table below with the results from the monosaccharide test experiment, and your conclusions based on those results.

With these absorbance numbers a concentration curve was constructed and the unknown solution was determined by finding the point of absorbance on the curve.

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.

After this, the solution was poured into a volumetric flask just about to the 1dm3 line and then it was left there to cool to the same temperature as the room before filling precisely to the 1dm3 line with distilled water. The molar mass of CuSO4.5H20 was 249.5 so that means 249.5g of copper sulphate was needed to dissolve, in order to make a standard solution, into 1dm3of distilled water. Following this, a linear dilution of the CuSO4.5H2O was made in order to be used to make a calibration curve after using the colorimeter to write down the absorbance of each sample. A linear dilution is diluted with distilled water in order for it to make the concentration weaker and weaker. For this investigation, the dilutions made ranged from 0.01 to 0.1 M/l . It was essential to only make up 10cm3

10 microliters of the sample is then added and the assay absorption is measured at 340nm. If absorbance was above 1.5, samples were diluted.

In Part C of the experiment, the process completed in Part B was performed again on the six Kool-Aid drink samples: black cherry, cherry limeade, grape, mixed berry, strawberry, and tropical punch. The cherry limeade, grape, mixed berry, and tropical punch samples were undiluted stock solutions that were used in the SpectroVis. The black cherry solution was diluted with a 2-fold dilution. The 3 mL of black cherry solution was diluted with 3 mL of deionized water. This was done because the Red 40 dye was too concentrated. The strawberry solution was first diluted by a 2-fold but the absorbances values were too high and fell outside the acceptable range of 0-1. Therefore, 8 mL of strawberry solution was diluted with 12 mL of deionized water. These values for all of the solutions were recorded in Table 5. The solutions were emptied down the sink. All the glassware and cuvettes were rinsed with deionized water and dried. The volumetric flasks and caps were returned to the appropriate containers.

In this experiment, there were 6 different test tubes, each containing a different amount of phosphate concentration. Using a balance, 1 g of phosphate in a 400 mL beaker was measured and then inserted into a 100 mL graduated cylinder. 5 mL of ammonium vanadomolybdate (AVM) was added, along with deionized water until the solution reached to 25 mL. Then the solution was poured into one of the six test tubes. Another test tube contained 2 g of phosphate (phosphate was again measured using the balance) and the step described earlier was repeated until five of the six test tubes were filled, each with the same volume of 25 mL. The sixth test tube was filled with only deionized water, with 25 mL as the volume. A spectrophotometer was then used to determine the percent transmittance for each solution. The absorbance was also calculated using the equation A = -log (T). Each given amount of phosphate was converted into moles and then applied the value of .025 L for the volume to calculate the molarity of phosphate in each solution.

An experiment was done to determine the concentration of Allura Red in a commercially available beverage, Gatorade. This was done by using the colorimeter, the absorbance of five Allura Red solutions were measured. The graph obtained demonstrated a linear relationship and the equation obtained yielded a concentration of 1.9910-6M.

Each stock solution was placed in a colorimeter and was tested for it Absorbance. A computer program tested and drew up the Calibration curve/linear fit equation. However, the computer could not protect potential errors. An error for determining the concentration of the diluted and undiluted, could be a skew linear fit equation. The linear fit equation could be skewed by having an inadequate ratio of the stock solution and distilled water. For example, when making stock solution 1, 0.021(L) was used instead of 0.020(L) can throw the calibration curve, resulting a skewed linear fit equation. If the “blank” was not fully clean or had left over Allura Red residue, then the “blank” was tampered with. A tampered “blank” means any comparisons with it would have a wrong Absorbance reading. However, the most likely and most effective error, is calculation. Using the wrong V1 and V2 to determine the concentration of the undiluted would affect the answer of the grams Allura Red would be consume and the amount of molecules of Allura Red. The colorimeter is adjusted to a wavelength of 470 nm is maximize the absorbance of the Allura Red. If wavelength was place at 565 nm, then Allura Red would not absorb as much color of

MANUAL Q5: What color of light is being absorbed by the sample solution? How is that color related to the color of the solution?

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

Using the yellow tube, which included everything but starch, as the blank, each group zeroed their spectrophotometer. This was done so that any absorbance observed depends only on the amount of starch present, not on any other reagents (buffer, IKI). To zero the spectrophotometer, the wavelength was first set at 580nm, using knob 3 (45). Next, the groups made sure that the light next to “transmittance” was lit, and the chamber to be tightly closed. Having the chamber empty & closed tightly provides reference for the darkest condition possible. Using knob 1, the transmittance was turned until it read 0.0 (45). Before the groups used their blank test tube to zero the spectrophotometer, each needed to wipe the tube with kimwipes to ensure a clean reading. Turning knob 2, each group was then instructed to zero the absorbance, 0.000. Upon removing the blank, each trial was inserted into the chamber (46). The

To be able to know how to conduct their experiment, the scientists researched how to use certain materials they will be using. One of the main materials they will be using will be a refractometer to measure the TDS of the black coffee and gun powder green tea. It works by putting a few drops of the beverage onto the sample well of the refractometer, where a small light beam shines through. The refractometer then calculates the amount of total dissolved solids and provides the percentage of TDS. (Fresh Cup Magazine,

The absorbance is measured using a Plate reader and a Standard curve is generated. Also, the different types of pipetting techniques are assessed in this Assay.

3 because this is the maximum absorbance for the iron (III) ion. The Beer's Law Plot that was graphed came out to be linear with an equation of: