Alka Seltzer and the Ideal Gas Law
Purpose – When Alka Seltzer reacts with water, CO2 gas is produced. In this lab, you will collect the gas given off from this reaction. Using the mass difference, you will determine the mass lost by the process, and thus the mass of CO2 produced. You will use the ideal gas law to calculate the number of moles of gas produced, and from this, the molar mass of CO2.
Materials: Erlenmeyer flask, Alka Seltzer tablets, mortar and pestle, 9-inch round balloon, scoop, thermometer, barometer, scissors
1. Fill a flask to overflowing with tap water.
2. Obtain 3 Alka Seltzer tablets and crush.
3. Get a large, round balloon and remove the air from it.
4. Place the tablets in the balloon and attach carefully to the flask (balloon hangs to side).
5. Use electrical tape or duct tape to secure the balloon tightly to the flask.
6. Place the balloon upright to start the reaction.
7. As the reaction continues, hold the balloon and invert the tube several times to ensure completion.
8. After all bubbling stops, measure the circumference of the balloon with a string. If the balloon is misshapen, try to push it into the shape of a sphere while measuring the circumference.
9. Place the system on the electronic balance. Record this mass.
10. Grab the top of the balloon and flatten a small section. Make a small cut in the balloon and slowly release the gas. Record the new mass. Be sure that no water leaves the balance.
11. Record the room temperature and the barometric pressure below.
1. Circumference of balloon:
2. Mass of system before releasing gas:
3. Mass of system after puncturing...