Reaction Rates: When Surface Area Matters! Lesson Plan Introduction


Chemical reactions can happen really fast,
whereas others, even when using the same starting materials, do not seem to happen at all. How a chemical reaction happens is explained
in the Collision Theory which states that reactant molecules have to collide in order
to form a product. If they collide in the wrong orientation,
however, no reaction will happen. If they collide without enough energy, no
reaction will happen. Only if they collide in the right orientation
and with enough energy, will products be formed. The more successful collisions happen, the
faster the chemical reaction rate. How can we increase the number of successful
collisions? In this activity, you will explore the effect
of particle size and surface area with the help of the Alka-Seltzer reaction – a bubbly
reaction based on mixing bicarbonate with acid in water. You will dissolve one whole tablet, one broken
tablet and one powdered tablet to measure which reaction will be the fastest. Will breaking the tablet into smaller pieces,
and increasing its surface area, change the reaction rate? Find out in this sparkling experiment!