Alka-Seltzer® Revisited
Investigate the reaction of Alka-Seltzer® tablets with water in an open system. Explain how some mass appears to be "lost."
Ohaus ScoutTM II Balance
(model #SR2020)
Lab Summary
Students will investigate the reaction of Alka-Seltzer tablets with water in an open system in order to explain how some mass appears to be "lost."
Citric acid (C6H8O7) and sodium bicarbonate (NaHCO3) are the main ingredients in Alka-Seltzer tablets. When the tablets are dropped into water and dissolved, hydrogen ions (H+) and carbonate ions (CO6-2) are freed to collide and react in the solution. The products of the reaction are water and carbon dioxide gas.
Hypothesize: When Alka-Seltzer tablets react with water in an open system, will the total mass of the system increase over time, decrease over time or remain the same? Explain your reasoning.
Published: April 2003
Downloads
- Alka-Seltzer® Revisited (18 KB, .zip)
Includes experiment setup and procedures
Here's What You Need
U.S. Educator prices shown.
Probeware (PASPORT Systems)
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
PASPORT Temperature Sensor (PS-2125) - $30
Durable stainless steel temperature sensor with a wide measurable range. For use with PASPORT Interfaces.
Other Products
OHAUS Scout Pro Balance 200g (SE-8823) - $355
Ideal for student labs and can be easily connected to DataStudio for data analysis.
Other Materials
- Alka-Seltzer tablets (2)
- 250-mL plastic beaker
- 100-mL graduated cylinder
- weighing paper, double-folded (so that creases in paper cradle the tablets)
- tap water
