In this demo, camphor particles are placed in water. They sublime at room temperature which is why camphor’s odor permeates the room so quickly. The gas that forms around the particles propels the particles in random directions. Earwax contains a large percentage of long chain fatty acids which form a monolayer in water, thus ceasing the motion of the camphor particles.
Under basic conditions glucose is oxidized while methylene blue is reduced, changing from blue to colorless. The reduction reaction can be reversed by shaking the flask which forces oxygen into solution, which oxidizes the methylene blue, thus turning it back to blue. If the flask is let sit, the oxygen will come out of solution making the solution colorless and ready to shake again.
When sugar is reacted with concentrated sulfuric acid it creates a black foam made of elemental carbon. The water that is produced in the reaction is gaseous and causes the foam to rise.
H2SO4 + C12H22O11 → 12C + 11H2O + a mixture of acid and water
When the balloon is rubbed on a pair of jeans, electrons are wiped from the jeans to the balloon, causing a net negative charge on the balloon. The charged balloon is held near a thin stream of water. Charges in the water rearrange so that the positive charges in the water become attracted to the negatively charged balloon, and the stream of water bends. The rearranging of charges is pronounced because water is a polar molecule.
When ammonium nitrate is dissolved in water it feels cold, which indicates an endothermic reaction.
NH4NO3 (s) → NH4+ (aq) + NO3- (aq)
This demo simulates what happens when Drano is poured down a clogged drain; the hydrogen gas produced forces gunk out of the drain. Also, this demonstration is a good safety example of why bases need to be handled carefully – they can be corrosive, especially to metals. If the hydrogen gas is collected and ignited, this demo shows the safety hazards that evolved gases can have.
2Al + 2NaOH + 6H2O → 2NaAl(OH)4 + 3H2
Friday April 8th, 2011: Casey presented on her research with demonstrations at the poster session.
Thursday March 3rd, 2011: The freshman chemistry majors at JMU learned how to do 3 demonstrations and tie-dye t-shirts.