EFFECT OF PARTICLE SIZE ON RATE OF REACTION
Big thoughts coming at you: The rate of a chemical reaction is affected by the physical size of the reactants. If this makes any sense to you then you are clearly a genius.
» 3 Clear glasses
» 3 original formula effervescent Alka-Seltzer tablets
» Mortar and pestle
Part A. Whole Tablet
- Fill a clear glass with exactly 8 oz./240 mL of room temperature or lukewarm water.
- Drop 1 whole Alka-Seltzer tablet into the water. Measure and record the time to dissolve.
Part B. Tablet Broken into ~8 Pieces
Place 1 Alka-Seltzer tablet onto a sheet of paper and break into approximately 8 pieces of about equal size.
Fill a clear glass with exactly 8 oz./240 mL of room temperature or lukewarm water.
Slide broken tablet into the water from the sheet. Measure and record the time to dissolve.
Part C. Powdered Tablet
Place 1 Alka-Seltzer tablet into mortar and grind to a fine powder.
Transfer powder into a clear glass. (Note: It's important to have the powder in the cup before adding water.)
Add 8 oz./240 mL of water to the glass. Measure and record the time to dissolve.
Decreasing the size of the particles, which make up a given weight, will increase the number of particles represented by the same weight. Smaller particle size results in an increase in the rate of reaction because the surface area of the reactant has been increased.