# Alka-Seltzer Reaction Rates Lab Assignment

Words: 812

Alka-Seltzer Reaction Rates Lab What are the different factors the effect the reaction rate of Alka-Seltzer? Matthew Arkfeld Leah Gilligan Jessie Abbott Period 4 June 2nd, 2008 Background Research: o The objective of the experiment was to determine if different factors affect the reaction rate of Alka-Seltzer. Alka-Seltzer provides fast relief to acid indigestion, upset stomach, heartburn, headaches, body aches and pains. It is an antacid and pain relief medicine used by millions of consumer’s everyday. It is sold at local pharmacies over the counter and supermarkets worldwide. The original Alka-Seltzer was invented in 1931, the active ingredients are: 325 mg of Aspirin, 1000mg of Citric Acid and 1916mg of Sodium Bicarbonate, designed to treat pain and simultaneously neutralize excess stomach acid. It is provided in the form of large effervescent tablets, which are dissolved in a glass of water. As the tablets dissolve, the base (bicarbonate) and the acid (citric acid) react vigorously producing carbon dioxide gas, which also produces enough agitation to allow the active ingredients to dissolve slowly. In our lab, our objective was to test if water at different temperatures, salt, and vinegar, would affect the reaction rate of Alka Seltzer tablets. However we thought, that the size of the tablet would not matter. Therefore, we decided to test Alka Seltzer broken into fragment and completely ground up as well as the normal tablet. Hypothesis and Variables: o Hypothesis: We believe that hot water, and vinegar will affect the rate of the reaction, however, the size of the tablet does not matter. Independent Variables: temperature of water (ice, room, hot), Size of tablet (whole, pieces, powdered), Solution it is in (tap, vinegar, salt water). o Dependent Variable: The rate of reaction of Alka-Seltzer. Materials: o 3-quart size jars, 3 Alka-seltzer tablets, ice water, room temperature water, hot water, stopwatch, thermometer, vinegar, salt, tablespoon. Procedure: 1. Fill one of the jars a third of the way with ice. Put tap water in it until it is half way full. Let it come to a stable temperature. 2. Fill the second jar half way filled with room temperature water. . Fill the third jar half way with hot tap water (run tap on hot for one minute). 4. Use the thermometer to record temperature for the three waters. Record in table. 5. Put an Alka-Seltzer tablet in each jar and use a stopwatch to record how many seconds it takes to dissolve. Do not stir or mix the tablet! Record all results. 6. Put all the liquids down the drain and rinse out jars throughouly with water. 7. Fill the jars half way with room temperature water. 8. In the first jar, place a whole Alka seltzer tablet. Record the time it takes for it to completely dissolve. 9.

Repeat step 9 with the Alka seltzer broken into 8-10 pieces. Record the time it takes to dissolve. 10. Repeat step 9 with the Alka-Seltzer tablet completely crushed into powder. (Crush between two pieces of paper with a hammer) Record the time it takes for it to completely dissolve. 11. Rinse all jars completely and throughout again. 12. Fill one jar half the way with room temperature water. Fill another jar one half full with vinegar. Finally fill the last jar half way with salt water. (2 tablespoons, room temperature). 13. Pour an Alka-Seltzer tablet in each jar and record time it takes to completely dissolve. 4. Observe your results. Observations and Data: | |Water Temperature |Time to Dissolve | |Ice Water |1 degree f |155 seconds | |Room Temperature |74 degrees f |47 seconds | |Hot Water |110 degrees f |24 seconds | |Time to Dissolve | |Whole Alka-Seltzer |45 seconds | |Broken into Pieces |40 seconds | |Powdered |11 seconds | |Time to Dissolve | |Tap Water |46 seconds | |Vinegar |68 seconds | |Salt Water |77 seconds |