Experiment 10: How much CO2?
The goal of this lab was to determine the amount of grams of sodium bicarbonate (NaHCO3) required to produce enough CO2 gas to completely fill the lab and also how many Alka-Seltzer tablets that would equate to. This was done by collecting CO2 gas by inverting a buret and submerging it under water in order to calculate the volume of CO2 released from a fragment of Alka-Seltzer tablet. The main component of Alka-Seltzer is sodium bicarbonate, used to neutralize excess stomach acid during illness through the following reaction that generates CO2: HCO3- + H+(aq) H2CO3(aq) CO2(g) + H2O
An Alka-Seltzer tablet was accurately weighed and recorded using a weighing boat and analytical balance. A fragmented piece between 0.2100g and 0.2800g was also weighed and recorded. 500mL of water was placed in a 600mL beaker. 80mL of water was then mixed with 20mL of 6M HCl in a 150mL beaker to create 1.2M HCl. A 1.5g piece of Alka-Seltzer tablet was then added to the HCl solution. After complete evolution of CO2, gravity filtration was used to catch all of the starch produced from the reaction. The buret was filled with the filtrated solution and the glass tube end of a rubber tube was inserted about 2 inches into the mouth of the buret. While keeping a finger over the buret mouth, the entire buret was quickly inverted and the tubing and mouth completely submerged into the water in the 600mL beaker. The buret was then clamped into place while double checking the buret mouth was under the water level and the rubber tubing was not pinched. The stopcock was then opened extremely slowly until the water level in the buret dropped close to the 50.00mL mark. This level was then recorded.
25mL of the prepared HCl solution was added to a 125mL Erlenmeyer flask, along with a 0.5-1.0g piece of Alka-Seltzer tablet. After complete evolution of CO2, the neck of the flask and rubber stopper were completely dried. The tablet fragment...
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