Chemistry Cola Lab

Kenneth Olivieri

Professor Pluhar

General Chemistry Lab

11/8/15

Analysis of Phosphate Concentration Levels in Different Colas Using a Spectrophotometer

Introduction:

​In this experiment, the measurement of phosphate levels present in 5 different colas were taken. These measurements of phosphate were obtained with the use of a spectrophotometer and ammonium vanadomolybdate. The objective for this experiment was to determine if soda brands contained the amount of phosphate as advertised by each brand.

Methods:

​For the first part of this experiment, before making any solutions, each soda was put on a hot plate for about 15min to get rid of any carbon present. Before making the dilutions of each soda, a blank solution for each soda was made. For example, coca cola blank solution consisted of 1mL coke and 9mL water. Then the dilutions of each soda were made and put into the spectrophotometer and examined. Once obtaining the results from the spectrophotometer and carrying out the formulas necessary to get the absorbance of the solutions, the concentrations of each soda were found by carrying out the formula Absorbance/Slope.

Results:

Table 1: Determining the Transmittance and Absorbance of blank and sample solutions for each cola.

Soda Type

Wavelength (Nm)

Blank (mL)

Sample (mL)

Transmittance

Absorbance

*2-log(trans)

Coca-cola

400Nm

1mL coke, 9mL water

1mL coke, 3mL AVM, 6mL water

13.5%

.87

Pepsi

400Nm

1mL pepsi, 9mL water

1mL pepsi, 3mL AVM, 6mL water

5%

1.30

Sure Fine diet cola

400Nm

1mL SFDC, 9mL water

1mL SFDC, 3mL AVM, 6mL water

6%

1.22

Adirondack

400Nm

1mL Adirondack, 9mL water

1mL Adirondack, 3mL AVM, 6mL water

2%

1.70

Waist Watchers

400Nm

1mL WW, 9mL water

1mL WW, 3mL AVM, 6mL water

13.3%

0.87

Table 1 represents all the data collected before it was used to find the absorbance of each soda brand through using the absorbance formula of 2-log(transmittance). *AVM (ammonium vanadomolybdate).

Table 2:...