In order to make a calibration curve for the phosphate, KH2PO4 or KH2PO4 can be used. The purpose of a calibration curve is to analyze certain substances and get a completely accurate understanding of that substances makeup. With the calibration curve, known information about the unknown substance can be used to estimate its properties and makeup. By drawing comparisons between the information about the unknown and information on the calibration curve, a prediction or estimation can be made about the composition of the unknown. In the case of the analysis of phosphate in the colas, phosphoric acid acts as the known compound. Only phosphate was measured. The usual range of phosphate concentration in colas is around 10^-3 and 10^-4M (Cooper,…show more content… However, the volume needed to dilute was necessary to be calculated using the formula. The volume was calculated to be .9901mL. .9901ml of KH2PO4 was diluted with 100 mL of water. The diluted KH2PO4 solution was then diluted again. The formula was used again to calculate the volume of water necessary to dilute. The V2 was .25 mL. .25 mL of the diluted solution was taken, and diluted again with 25 mL of water. The final solution had a concentration of .0002M KH2PO4. Three other solutions of KH2PO4 were made with different concentrations, and were used to create the calibration…show more content… A blank was prepared with a 2:1 ratio of water and AVM. 4 mL of water and 2mL of AVM was used. The KH2PO4 was measured for %T at 50 nm increments from 350 nm to 650 nm. The wavelength of 400 had the lowest %T, therefore, the highest absorbance, and was the analytical wavelength. The other concentrations were also measured in the Spec 20 for their absorbances. The calibration curve was created by plotting the concentration vs absorbance. The linear relationship created a line y = 21818.3x + .1196 with an R^2 = .86419. To find the concentration of PO4 in cola samples, the colas were first degassed. The colas had to be diluted in order to be measured for &T in the Spec 20. The colas were diluted in 50:1 ratio, with 50 mL of water and 1mL of soda. The diluted sodas were then diluted again with a 2:1 ratio of AVM. 10 mL of the dilute cola was mixed with 5mL of AVM. A sample of each kind of soda and its AVM was placed in a beaker. Beaker one contained the diluted coke and AVM, beaker two contained diet coke and AVM, and beaker three contained red soda and AVM. The different sodas were placed in Spec 20, and measured at 400 nm. Diet coke had absorbance of .18, coke had an absorbance of .276, and red soda has an absorbance of .142. The following equation was used to find out the different concentrations: y= mx+b. The equation y= 2181.3x +.1196 for the phosphoric