Amazing Fire Trick!

from wikipedia

A candle is a solid block of fuel (commonly wax) and an embedded wick (mecha in spanish), which is lit to provide light, and sometimes heat.

The heat of the match used to light the candle melts and vaporizes a small amount of fuel. Once vaporized, the fuel combines with oxygen in the atmosphere to form a flame (combustion). This flame provides sufficient heat to keep the candle burning via a self-sustaining chain of events: the heat of the flame melts the top of the mass of solid fuel, the liquefied fuel then moves upward through the wick via capillary action, and the liquefied fuel is then vaporized to burn within the candle's flame.

When a candle is put off there is still wax being vaporised for a while which does not have enough energy to ignite and which is normally seen as smoke current (formed mainly by wax particles, carbon particles from deficient combustion and water vapour). This smoke current, still containing combustible particles, can be lighted again working as a gas wick until the flame reaches the real one igniting the candle again!!

Chromatography

It is a bit long and the music just does not match at all but this video nicely illustrates the principles of the most important separation technique...CHROMATOGRAPHY!

Massive Single Crystal!!!

I never thought that something like this was possible!!....

This is a synthetic seed crystal. It is placed in a six-foot-high tank filled with nearly a metric ton of supersaturated potassium dihydrogen phosphate (KH2PO4), or KDP. As it rotates on a turntable in the tank, the crystal begins to grow. In just two months, the crystal grows to be as large as 800 pounds; with conventional methods of growing crystals, this process would take nearly two years. When complete, the crystal is carefully cleaned. It's removed from the tank. Then it's measured; and finally, it's cut into 40-by-40-centimeter plates to be used in the National Ignition Facility to focus, transmit and direct laser beams on their way to the target chamber.

Manganese Heptoxide oxidizing a potato chip

from wikipedia
Mn₂O₇ arises as a dark green oil by the addition of concentrated H₂SO₄ to KMnO₄. The reaction initially produces permanganic acid, HMnO₄ (structurally, HOMnO₃), which is dehydrated by sulfuric acid to form its anhydride, Mn₂O₇.

2 KMnO₄ +(cold) 2 H₂SO₄ → Mn₂O₇ + H₂O + 2 KHSO₄

Mn2O7 is a volatile liquid highly reactive being a powerful oxidiser. It is able to oxidise (burn), no sparks needed, any sort of organic matter...sugar, hydrocarbons, paper, and even a potao chip!!!....

MAKING ZnS

Zn + 1/8 S8 = ZnS


Zn just gets oxidised to Zn+2 by 1/8 S8 that gets reduced to S2- forming ZnS which is a mineral also called blende or sphalerite

Making Nylon

Nylon is a polymer made by the condensation reaction between a diacid and a diamine. The acid and amine groups join together forming amide links realising water (this is why it is called condensation reaction)...

Vinegar, Bicarbonate and Candles!!

NaHCO3 (Sodium Bicarbonate) + HOOCCH3 (from vinegar) = H2CO3 (Carbonic Acid) + NaOOCCH3(Sodium acetate

H2CO3 decomposes to CO2 (gas) + H2O

CO2 is a heavier gas than air so when the jar is put near the candles the CO2 coming out of the jar pushes away the air surrounding the candles putting them off...

Braniac - The danger of nylon

Static electricity generated on your nylon clothes when they rub against your skin are enough to fire a bomb!!

Oxygen in Air

Air composition is:

Nitrogen N2 78.084 %
Oxygen O2 20.9476 %
Argon Ar 0.934 %
Carbon Dioxide CO2 0.0314 %
Neon Ne 0.001818 %
Methane CH4 0.0002 %
Helium He 0.000524 %
Krypton Kr 0.000114 %
Hydrogen H2 0.00005 %
Xenon Xe 0.0000087 %

...and this is one way to meausure the amount of O2 than contains (21 %) through the oxidation reaction of Cu to CuO...

Amazing Crystal Cave

The BIGGEST CRYSTALS in the world!! Some of them are more than 10 meters long!! They are made of selenite which is a form of gypsum (Spanish: yeso). Its formula is CaSO4.2 H2O.

Cave of the Crystals (from wikipedia)or Giant Crystal Cave (Spanish: Cueva de los Cristales) is a cave in Mexico. The main chamber contains giant selenite crystals, some of the largest natural crystals ever found. The cave's largest crystal found to date is 11 m (36 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight. The cave is extremely hot with air temperatures reaching up to 58 °C (136 °F). The cave is relatively unexplored due to the extreme temperatures and high humidity. Without proper protection people can only endure approximately ten minutes of exposure at a time.

The Periodic Table of Videos

THE PERIODIC TABLE OF VIDEOS

This awesome web has a video of each element in the periodic table. And much more....

calcium in water

I have always pictured calcium as a white solid, maybe because its presence in milk or bones...however, pure calcium it is a silvery metal that reacts quite violently with water...

Ca(silvery metal) + 2 H2O = Ca(OH)2 (white solid, a bit soluble in water) + H2 (gas)

Phosphorus

Phosphorus is EVIL!!!  P4 + 5O2 = 2 P2O5 + a lot of heat....among other lots of bad things!!

New Section: SCIENCE HISTORY

The first episode of an outstanding BBC series about History of Chemistry inagurates our new section of Science History. Check it out!!!!

BBC |Chemistry: A Volatile History | Ep1 Discovering the Elements

 PART 1   PART 2   PART 3   PART 4   PART 5   PART 6

 

Egg and Vinegar Experiment

Acid-Base reaction:


CaCO3 (calcium carbonate) + 2 HOOCCH3 (acetic acid) = Ca(OOCCH3)2 (calcium acetate) + H2CO3 (carbonic acid)

The CaCO3 from the egg shell is a hard solid (it is the main component of for instance stalactites) and when it reacts with the acetic acid that vinegar contains forms Ca(OOCCH3)2 that is a powdery solid soluble in H2O. The carbonic acid released is unstable and decomposes into CO2 (gas bubbles around the egg shell) and H2O.

Beautiful reaction between bromine and aluminium

This is a REDOX reaction followed by an ACID-BASE one


2 Al + 3 Br2 (red liquid) = 2 AlBr3

AlBr3 + 3 H2O (from air) = Al(OH)3 + 3 HBr (red gas)

Hydrochloric acid bomb

3 HCl + Al = AlCl3 + 3/2 H2   

Egg trick learn how now

In the youtube video comments there is this great explanation:

"when the matches burn, they heat up the air inside the bottle and release steam n causes the air inside the bottle to expand, forcing some out of the bottle, egg seals the top of the bottle, matches run out of oxygen and go out, the air in bottle cools, volume of air inside the bottle drops due to condensation of the water vapor and the cooling of dry air....exerts less pressure on the egg b/c the air pressure outside of the bottle doesn't change.. overcoming friction :D .."

Chemical volcano

Ammonium dichromate (NH4)2Cr2O7 decomposes when heated yielding green chromium(III) oxide, nitrogen and water vapor. It is a comproportionation reaction where Cr(+6) of Cr2O7(2-) gets reduced to Cr(+3) of Cr2O3 oxidising N(-3) of NH4(+) to N(0) of N2 gas. Also some H2O is released but it does not involve any REDOX process.

Visualization of Mercury vapors in UV light

Mercury and most of its compounds are extremely toxic. It has to be handled with care because it is liquid at or near room temperature and pressure and therefore its vapors are really toxic. These toxic vapors are invisible under normal light but as this video nicely shows they are there!!!