IODINE SUBLIMATION

 from wikipedia

Iodine (I2) under standard conditions is a metallic like bluish-black solid. When heated it sublimates (it directly goes from solid phase to gas phase) into a violet-pink gas that has an irritating odor. This iodine gas can condensate on a cold surface forming nice crystals of iodine solid. This process can be used to purify iodine.

MAGNETIC LIQUID

by basco36
A liquid magnet or ferrofluid (from video description) is a colloidal mixture of magnetic particles (~10 nm in diameter) in a liquid carrier. The carrier contains a surfactant to prevent the particles from sticking together. Ferrofluids can be suspended in water or in an organic fluid. A typical ferrofluid is about 5% magnetic solids (magnetite, hematite or any other substance containing iron), 10% surfactant (oleic acid, citric acid, soy lecitin, etc) and 85% carrier (solvent), by volume.

UNIVERSAL INDICATOR

video from ChemToddler and explanation from wikipedia

A universal indicator is present in a water solution at pH = 14 (purple colour) while an acid is slowly added turning the solution colour to blue, green, yellow and finally red when the pH goes down to 0. The bottom part of the beaker solution goes slower to lower pH when at the top local acid conditions are always observed until an homogeneus pH is obtained

A Universal indicator is a pH indicator composed of a blend of several compounds that exhibits several smooth colour changes over a pH value range from 1-14 to indicate the acidity or basicity of solutions.

A universal indicator is typically composed of water, propan-1-ol, phenolphthalein sodium salt, sodium hydroxide, methyl red, bromothymol blue monosodium salt, and thymol blue monosodium salt.

The colours that indicate the pH of a solution, after adding a universal indicator are:

pH range	Description	Colour
0-3	Strong acid	Red
3-6	Acid	Orange/Yellow
7	Neutral	Green
8-11	Base	Blue
11-14	Strong Base	Purple

Underwater Fireworks: Sparklers

by thirstforscience

A sparkler (from wikipedia) is a type of hand-held firework that burns slowly while emitting colored flames, sparks, and other effects. They rely on REDOX reactions and therefore they contain two main components:

FUEL (reducing agent). There are two types:

• Metallic fuel, mandatory to make sparks; size of particles influences appearance of the sparks
• Aluminium or magnesium or magnalium, producing white sparks
• Iron, producing orange branching sparks
• Titanium, producing rich white sparks
• Ferrotitanium, for yellow-gold sparkles
• Additional fuel, optional, modifying the burning speed
• Sulfur
• Charcoal

OXIDIZER (oxidant agent). There are several types

• Potassium nitrate
• Barium nitrate
• Strontium nitrate
• Potassium perchlorate, more powerful but potentially explosive

As the sparklers contain their own oxidizer they don´t need to be in contact with air to burn out and therefore they work underwater!!

 

BBC |Chemistry: A Volatile History | Ep2 The Order of the Elements

Second episode of the BBC series about History of Chemistry

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

EXPLOSIVE copper oxide reduction with aluminium

from drgleisner 

Very nicely explained thermite type reaction where Al metal (aluminium 0) reduces CuO (copper +2) to form Cu metal (copper 0) and Al2O3 (Al +3) after some induction period on a Bunsen burner. Check out the reaction of the young audience!!

This is the redox process involved:

3 CuO  + 2 Al  = 3 Cu + Al2O3

Violent Hydrogen peroxide 85% decomposition

The decomposition of hydrogen peroxide consists formally in a redox reaction between two molecules of H₂O₂, one acting as a reducing agent and the other as oxidant. This is the overall reaction named disproportionation:

2 H₂O₂ = 2 H₂O + O₂(gas)

This decomposition is easier when concentrated H₂O₂ is used and can be catalysed by bases, light (hydrogen peroxide bottles are not transparent), or metals as it is shown on this video. In other words hydrogen peroxide can be considered as a reservoir of oxygen and this explains its oxidising properties.

SODIUM POLYACRYLATE demonstration (FAKE SNOW!!)

from wikipedia

Sodium polyacrylate, also known as waterlock, is a polymer with the chemical formula [-CH₂-CH(COONa)-]_n widely used in consumer products. It has the ability to absorb as much as 200 to 300 times its mass in water. Acrylate polymer possess an anionic charge neutralized by the sodium cations. The polymer embrace water molecules through hydrogen bonds (the anionic charges  along the polymer interact with water hydrogen atoms and cationic sodiums with the water oxygen atoms). It is used for instance in baby nappys/diapers (pañales in spanish).

NUCLEAR FUSION

Nuclear fusion is definitely the future of global energy needs...check out on this video the creation of a small sun contained inside a magnetic field!!

COLOURFULL OXIDATION STATES OF VANADIUM

Sodium Vanadate (NaVO₃) is dissolved in diluted HCl giving a solution containing (VO₂)Cl through a dehydration (acid-base) reaction that also releases 2H₂O and NaCl (I made this up but I guess it is what actually happens):

NaVO₃ + 2 HCl = NaCl + H2O + (VO₂)Cl

(VO₂)Cl in solution gives YELLOW VO₂⁺ cations (Vanadium +5) which can be sequentially reduced (Zn-Hg amalgam) to BLUE VO²⁺ (Vanadium +4), to GREEN V⁺³ and finally to LAVANDER V⁺².

Color Change Gemstone

This gemstone is green under fluorescent light and pink under incandescent light. This is probably due to a phenomenom called dichroism.

NEW CHEMISTRY JOURNAL

A new chemistry journal has emerged.....by now it is just in spanish but there will be an english version soon...

http://www.laquimicatoday.blogspot.com/

Yuri Gagarin: 50th Anniversary of First Human Spaceflight "First Orbit" Trailer

from video despriction

On 12th April 2011 it will be 50 years to the day since Yuri Gagarin climbed into his space ship and was launched into space. It took him just 108 minutes to orbit Earth and he returned as the World's very first space man. To mark this historic flight Chrisopher Riley has team up with the astronauts on board the International Space Station to film a new view of what Yuri would have seen as he travelled around the planet. A spellbinding film has been created to share with people around the World on this historic anniversary YouTube will host a special global premiere of the film on the 12th April (TODAY!!). This is the trailer of the filtm FIRST ORBIT, that I "think" you can download from here

Liquid Nitrogen and the spinning ping pong ball

Modern liquid nitrogen version of Hero of Alexandria Aeolipile steam machine!!

Galvanic cell

Redox reaction between Zn and Cu+2 can be used to make a galvanic cell as it is nicely explained in this video

Nitrogen Triiodie gets grumpy!!

from wikipedia

Nitrogen triiodide is the inorganic compound with the formula NI3. It is an extremely sensitive contact explosive: small quantities explode with a gunpowder-like snap when touched even lightly, releasing a purple cloud of iodine vapor and nitrogen gas.

The decomposition of NI3 is a redox reaction that proceeds as follows to give nitrogen gas and iodine:

2 NI3 (s) → N2 (g) + 3 I2 (g)

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!!