The purpose for this experiment is to determine the amount of Carbon carbonate in a Tums tablet, using the ideal gas law for three trials. We will measure and record the results of the three trials, using the same method. By using gas laws and stoichiometry, we will be able to determine the mass of CaCO3 in the Tums tablet. This information can be used to calculate the percentage of CaCO3 in Tums. .
In order to perform this experiment, we first weighed and ground the tablet up. The powder is placed in a closed beaker, with a tube connecting to an inverted graduated cylinder. The graduated cylinder is filled with water, and placed upside down in the bucket of water. When the cylinder is lifted up around 1 or 2 inches from the bucket's bottom, the water started decreasing, as the CO2 took its place in the cylinder. We recorded the point where the water stopped decreasing completely. We repeated the experiment for two more trials with the same procedure. .
The pressure of all the gas in the cylinder, is equal to atmospheric pressure. The CO2 collected has water vapor. We used the vapor pressure chart to calculate the pressure of C02. According to the vapor pressure chart, water pressure was 21.1mmHg. We calculated CO2 pressure by subtracting water pressure 21.1mmHg by atmospheric pressure. Our result was 746.9mmHg or 0.983 atm.
In order to calculate mass of CaCO3 in the tablet, we need to find the number of moles of CO2. The number of moles of CaCO3 in the Tums, equal to the number of moles in CO2 produced. Therefore, used the PV=nRT idea gas law converted to n=(PV)/RT to find the number of moles in CO2. The average volume was 0.209 litters, CO2 pressure was 0.983atm, and temperature was 296.45K. We divided R constant and temperature by CO2 pressure and volume. CO2 number of moles was 0.008442mol. Then, we used number of molecules and molar mass of CO2 to find mass of CO2. As the CO2 equals CaCO3 number of molecules, we multiply the CO2 number of molecules by the molar mass of CaCO3 100.
