0912A

This Science Center trip was indeed an enriching one as we got to see the different Amazing Chemistry Experiments, which were

1. The Invisible Ink
2. Think Ink
3. Light Stick
4. Elephant Toothpaste
5. Silver Mirror
6. Genie In The Bottle
7. Super Absorbent Polymer
8. Dragon Fire
9. Cloth Burning
10. Blue Bottle Experiment

These experiments had shown us how Chemistry is closely related to our daily life and the amazing things brought about by the reaction between the different chemicals.

The experiment that impressed me the most were the Silver Mirror and the Super Absorbent Polymer while the most interesting experiment was the light stick.

Silver Mirror

Chemicals needed :

1. Silver Nitrate
2. Potassium Hydroxide
3. Glucose (dextrose)
4. Ammonia solution
5. Nitric Acid
6. Water

The "mirror" was formed because of redox reaction.

Overall equation:

CH3CH2CHO(aq) + 2[Ag(NH3)2]+(aq) + 3OH-(aq) → 2Ag(s) + CH3CH2COO-(aq) + 4NH3(aq) + 2H2O(l)

Video:

Super Absorbent Polymer

It can absorb and retain extremely large amounts of a liquid relative to its own mass (about 500 times its mass). It absorb aqueous solutions through hydrogen bonding with the water molecule. However, when put into a 0.9% saline solution, the absorbency drops to maybe 50 times its weight as the presence of valent cations in the solution will impede the polymers ability to bond with the water molecule.

Some of its uses include Diapers and Medical waste solidification.

Let the video shows how it works

Elephant toothpaste

Hydrogen peroxide (H2O2) decomposes into water and oxygen gas, but normally the reaction is so slow as to be imperceptible.

2H2O22H2O + O2 (G)

What happens when you pour hydrogen peroxide onto a cut? It bubbles! That's because there is something in your bodily fluids that catalyzes the reaction. A catalyst is a substance that speeds up a reaction, without being consumed itself.

In this demonstration we use a 30% hydrogen peroxide solution, which is much more concentrated than the 3% solution you can buy in the store. The production of oxygen gas is made more noticeable by adding some dish soap, which makes the foam. The reaction is catalyzed by iodide ion (I-) from potassium iodide. The iodide ion changes the mechanism, or pathway, by which the reaction occurs. In the first step of a two step process, iodide ion reacts with hydrogen peroxide to form water and the hypoiodite ion (IO-). This hypoiodite ion reacts with another molecule of hydrogen peroxide, giving water, oxygen, and iodide ion.

Notice that the iodide ion is regenerated, allowing it to go back and react with another molecule of hydrogen peroxide. This can continue for thousands of cycles. Note, too, that if one adds these two steps together, the I- and OI- cancel out, giving the same net reaction as above. The iodide is neither produced nor consumed in the reaction, but it changes the reaction mechanism, causing it to go faster. The rapid production of bubbles of oxygen gas, along with the dish soap, quickly creates a large quantity of foam.

Light Stick

It Contain :
1. Hydrogen peroxide solution
2. A solution containing a phenyl oxalate ester
3. Fluorescent dye.

This is what happen within the light stick :
1. The hydrogen peroxide which is the activator oxidises the phenyl oxalate ester, resulting in a chemical called phenol and an unstable peroxyacid ester.
2. The unstable peroxyacid ester decomposes, resulting in additional phenol and a cyclic peroxy compound.
3. The cyclic peroxy compound decomposes to carbon dioxide.
4. This decomposition releases energy to the dye.
5. The electrons in the dye atoms jump to a higher level, then fall back down, releasing energy in the form of light.

That's all about it.