Key concepts Introduction Background To take the tablets, they're fully dissolved in water, where they famously undergo a chemical reaction that produces lots of carbon dioxide bubbles—or fizz. Why is this? As the tablets dissolve, the sodium bicarbonate splits apart to form sodium and bicarbonate ions. The bicarbonate ions react with hydrogen ions from the citric acid to form carbon dioxide gas (and water). This is how the bubbles are made. How is temperature related to this reaction? For the reaction to occur, the bicarbonate ions must come into contact with the hydrogen ions in just the right way. The probability of the bicarbonate and hydrogen ions doing this is affected by temperature: the higher the temperature, the faster the molecules move; the lower the temperature, the slower they move. (The temperature of a solution is a measure of its molecules’ average motion and energy.) Can you guess whether fast-moving molecules or slow-moving ones will speed the reaction time? Materials Preparation Procedure Observations and results After the Alka-Seltzer tablet was added to the hot water the tablet should have quickly dissolved, taking some 20 to 30 seconds to do so, depending on the exact temperature. After the tablet was added to the ice-cold water it should have taken much longer to dissolve, with most of the tablet disappearing after about two to three minutes, but with some bubbles still apparent after six minutes or longer. In the hot water the tablet should have more vigorously produced bubbles than in the cold water. The higher the temperature, the faster the molecules move—and the more likely it is that the bicarbonate will contact hydrogen in just the right way for the chemical reaction to occur and produce carbon dioxide bubbles. More to explore This activity brought to you in partnership with Science Buddies ABOUT THE AUTHOR(S)Does AlkaIn short: the medicine dissolves fast and goes to work instantly, neutralizing acid on contact. Because the medicines in Alka-Seltzer effervescents are in solution prior to ingestion, they do not require time to dissolve in the stomach like similar active ingredients taken in a tablet form.
How do you know AlkaAlka-Seltzer and other fizzing tablets produce carbon dioxide-filled bubbles when placed in water. As the carbon dioxide is produced, you can see bubbles grow and float to the surface of the water. You may even be able to hear the bubbles as they pop.
How fast do AlkaAfter the Alka-Seltzer tablet was added to the hot water the tablet should have quickly dissolved, taking some 20 to 30 seconds to do so, depending on the exact temperature.
What does an AlkaThis medication is used to treat symptoms caused by too much stomach acid such as heartburn, upset stomach, or indigestion. It is an antacid that works by lowering the amount of acid in the stomach. Check the ingredients on the label even if you have used the product before.
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