23 Dec 2011
CHEMICAL REACTIONS COMPILATION
A compilation of chemical reactions performed by the people of The Periodic Table of Videos....
11 Dec 2011
23 Oct 2011
Iron Wool Balance
from chempics
The reaction occurred is just the oxidation (redox reaction) of iron
4Fe + 3O2 = 2 Fe2O3 plus lots of energy
Iron need to be very fine divided (wool) to allow the combustion keep going (the activation energy burn iron is really high in comparison to other combustible materials as gasoline, wood or carbon) and as Fe2O3 is a solid (a normal burn, for instance of a piece of carbon, releases CO2 gas) the combustion result is heavier...
very nice experiment!!
The reaction occurred is just the oxidation (redox reaction) of iron
4Fe + 3O2 = 2 Fe2O3 plus lots of energy
Iron need to be very fine divided (wool) to allow the combustion keep going (the activation energy burn iron is really high in comparison to other combustible materials as gasoline, wood or carbon) and as Fe2O3 is a solid (a normal burn, for instance of a piece of carbon, releases CO2 gas) the combustion result is heavier...
very nice experiment!!
28 Jun 2011
COMPARING THE FOUR HALOGENS
from oulearn
Have a look especially to the reactions of bromine and iodine with aluminium...simply spectacular!!
Have a look especially to the reactions of bromine and iodine with aluminium...simply spectacular!!
29 May 2011
FRACTIONAL DISTILLATION
by lowlevelpanic999
(from wikipedia) Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation. Generally the component parts boil at less than 25 °C from each other under a pressure of one atmosphere (atm). If the difference in boiling points is greater than 25 °C, a simple distillation is used.
(from wikipedia) Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation. Generally the component parts boil at less than 25 °C from each other under a pressure of one atmosphere (atm). If the difference in boiling points is greater than 25 °C, a simple distillation is used.
24 May 2011
SUPERFLUID HELIUM
video from BBC documentary Absolute Zero and explanation from wikipedia
Superfluidity is a state of matter in which the matter behaves like a fluid without viscosity and with infinite thermal conductivity. The substance, which looks like a liquid, will flow uncontrollably, and also will be at exactly the same temperature throughout itself. Despite its lack of viscosity, the liquid still has surface tension which allows it to rise up the sides of its container without the normal restrictions of flow. This allows the liquid to "flow" up the sides of the container and over the top.
Superfluidity is a state of matter in which the matter behaves like a fluid without viscosity and with infinite thermal conductivity. The substance, which looks like a liquid, will flow uncontrollably, and also will be at exactly the same temperature throughout itself. Despite its lack of viscosity, the liquid still has surface tension which allows it to rise up the sides of its container without the normal restrictions of flow. This allows the liquid to "flow" up the sides of the container and over the top.
7 May 2011
FIREFLIES in a flask experiment
by basco36
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 Cr2O72- gets reduced to Cr(+3) of Cr2O3 oxidising N(-3) of NH4+ to N(0) of N2 gas. This process needs quite a lot of energy to get started and it can be used to simulate a chemical volcano. However, if hot (NH4)2Cr2O7 is put in contact with NH3(g) (ammonia), obtained from a saturated NH4OH solution, the comproportionation is much faster as it can be seen on this video...
1 May 2011
MUSIC VIDEO Rube Goldberg Machine version
from wikipedia
A Rube Goldberg machine, device, or apparatus is a deliberately over-engineered machine that performs a very simple task in a very complex fashion, usually including a chain reaction. The expression is named after American cartoonist and inventor Rube Goldberg.
This music video, by the American band OK GO very nicely illustrates the principles of a Rube Goldberg machine....
A Rube Goldberg machine, device, or apparatus is a deliberately over-engineered machine that performs a very simple task in a very complex fashion, usually including a chain reaction. The expression is named after American cartoonist and inventor Rube Goldberg.
This music video, by the American band OK GO very nicely illustrates the principles of a Rube Goldberg machine....
30 Apr 2011
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.
26 Apr 2011
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.
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.
25 Apr 2011
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 |
24 Apr 2011
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!!
21 Apr 2011
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
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
19 Apr 2011
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.
18 Apr 2011
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).
17 Apr 2011
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!!
16 Apr 2011
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
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