from chemToddler
D2O, colloquially referred as heavy water, is normal water (H2O) highly enriched in the hydrogen isotope deuterium, which is twice as heavy as normal hydrogen. Deuterium oxide (D2O) it is about 11% denser than water, but otherwise, is physically and chemically similar. This video nicely explains this heavy water term.
3 Mar 2012
29 Feb 2012
Lightbulb in liquid nitrogen
from TheBlueginjava
A bare wolfram lightbulb filament in a beaker of liquid nitrogen can be connected to an electric current safely and without decomposition of the filament, shining as a normal lightbulb. The liquid nitrogen is a non conductive and almost inert material that isolates the wolfram filament from the atmospheric oxygen that would burn it out. The video explains it very well!!
A bare wolfram lightbulb filament in a beaker of liquid nitrogen can be connected to an electric current safely and without decomposition of the filament, shining as a normal lightbulb. The liquid nitrogen is a non conductive and almost inert material that isolates the wolfram filament from the atmospheric oxygen that would burn it out. The video explains it very well!!
25 Feb 2012
Liquid Nitrogen Explosion
Steve Spangler Science
Liquid nitrogen (boiling point -196 ºC) evaporates very quickly (explosively) in contact with hot water....
Liquid nitrogen (boiling point -196 ºC) evaporates very quickly (explosively) in contact with hot water....
Brainiac Alkali Metals
from scientist303
Alkali metals react with water reducing its protons to H2(g) and leaving an alkaline aqueous solution due to alkali metal hydroxide formation. When going down in the group from lithium to cesium the alkali metals give its electrons to the protons of water more easily and the reaction goes faster. As the reaction release heat, if this heat cannot be dissipated quickly enough the hydrogen released will get ignited, sometimes very violently, and react with atmospheric oxygen forming water again.
M(s) + H2O(l) = M(OH)(ac) + 1/2 H2(g) + lots of energy(*)!!...
H2(g) + ½ O2(g) + ignition energy(*) = H2O (g)!! + lots of energy!!...
Alkali metals react with water reducing its protons to H2(g) and leaving an alkaline aqueous solution due to alkali metal hydroxide formation. When going down in the group from lithium to cesium the alkali metals give its electrons to the protons of water more easily and the reaction goes faster. As the reaction release heat, if this heat cannot be dissipated quickly enough the hydrogen released will get ignited, sometimes very violently, and react with atmospheric oxygen forming water again.
M(s) + H2O(l) = M(OH)(ac) + 1/2 H2(g) + lots of energy(*)!!...
H2(g) + ½ O2(g) + ignition energy(*) = H2O (g)!! + lots of energy!!...
Plastic sulfur
from chemToddler
I have never seen this typical lab demonstration so well performed!!....the most amazing thing is that this grouse black polymeric sulfur goes back to its yellow powdery S8 form if you give it some time...
I have never seen this typical lab demonstration so well performed!!....the most amazing thing is that this grouse black polymeric sulfur goes back to its yellow powdery S8 form if you give it some time...
23 Feb 2012
SUGAR AND KClO3
from nuclearrabbit
Under thermal conditions or ignited by sulfuric acid, KClO3(s) decomposes to KCl(s) and 3/2 O2(g), which is a disproportionation reaction. The O2(g) generated oxidises very quickly carbohydrates as sucrose, C12H22O11(s,) liberating lots of heat, CO2(g) and H2O(g)...the presence of a bit of CuCl2(s) gives the bluish colour to the flames...very spectacular!!...
Under thermal conditions or ignited by sulfuric acid, KClO3(s) decomposes to KCl(s) and 3/2 O2(g), which is a disproportionation reaction. The O2(g) generated oxidises very quickly carbohydrates as sucrose, C12H22O11(s,) liberating lots of heat, CO2(g) and H2O(g)...the presence of a bit of CuCl2(s) gives the bluish colour to the flames...very spectacular!!...
21 Feb 2012
Conductivity of Glass
from NatSciDemos
Insulating glass becomes a conductor of electricity when heated with a blowtorch.
At the beginning I thought it was a fake as when heating the remains of the broken bulb, the two metallic filaments inside it were put into contact again. However, the changes observed on the intensity of the working bulb when changing the temperature of the "glass switcher" make me thought that this is well real!!
Two ceramic lightbulb sockets are wired in series to a household AC power cord. When two incandescent bulbs of the same Wattage rating are screwed into the sockets and the cord is plugged in, they both pass the same amount of current and so they both light with the same intensity. When one bulb is unscrewed, the circuit is broken and the other bulb goes out. If we can replace the missing bulb with a conductive material, the circuit will once more be complete and the remaining bulb will light again.
Insulating glass becomes a conductor of electricity when heated with a blowtorch.
At the beginning I thought it was a fake as when heating the remains of the broken bulb, the two metallic filaments inside it were put into contact again. However, the changes observed on the intensity of the working bulb when changing the temperature of the "glass switcher" make me thought that this is well real!!
Two ceramic lightbulb sockets are wired in series to a household AC power cord. When two incandescent bulbs of the same Wattage rating are screwed into the sockets and the cord is plugged in, they both pass the same amount of current and so they both light with the same intensity. When one bulb is unscrewed, the circuit is broken and the other bulb goes out. If we can replace the missing bulb with a conductive material, the circuit will once more be complete and the remaining bulb will light again.
18 Feb 2012
14 Feb 2012
Thermoelectric generator
from henders007
The thermoelectric effect refers to phenomena by which either a temperature difference creates an electric potential or an electric potential creates a temperature difference. Converting temperature to current is known more specifically as the Seebeck effect.
This effect has been used for decades to power space vehicles (Apollo ,Voyager probes, Mars rovers, etc..) using radioisotope thermoelectric generators, where the heat released by the radioctive materials is converted into electricity using an array of thermocouples.
Commonly used thermoelectric materials in such applications are semiconductors, as for example bismuth telluride (Bi2Te3).
What are the car companies waiting for to install these devices in our cars!!
The thermoelectric effect refers to phenomena by which either a temperature difference creates an electric potential or an electric potential creates a temperature difference. Converting temperature to current is known more specifically as the Seebeck effect.
This effect has been used for decades to power space vehicles (Apollo ,Voyager probes, Mars rovers, etc..) using radioisotope thermoelectric generators, where the heat released by the radioctive materials is converted into electricity using an array of thermocouples.
Commonly used thermoelectric materials in such applications are semiconductors, as for example bismuth telluride (Bi2Te3).
What are the car companies waiting for to install these devices in our cars!!
13 Feb 2012
11 Feb 2012
HYDROGEN AND CHLORINE
from chempics
H2 + Cl2 = 2 HCl
For the reaction to start an initiator is needed in order to overcome the activation energy. This can be a flame (as in this video) or just UV light...
VERY NICE LABCOAT by the way!!!
H2 + Cl2 = 2 HCl
For the reaction to start an initiator is needed in order to overcome the activation energy. This can be a flame (as in this video) or just UV light...
VERY NICE LABCOAT by the way!!!
8 Feb 2012
FARTING DRY ICE
from Chazmolanicus
The rapid expansion of CO2 when dry ice comes into contact with another surface results in some interesting sounds as it tries to escape.....really FUNNY!!
The rapid expansion of CO2 when dry ice comes into contact with another surface results in some interesting sounds as it tries to escape.....really FUNNY!!
4 Feb 2012
1 Jan 2012
THE BARKING DOG REACTION
The Barking Dog demonstration is based on an exothermic reaction between nitrous oxide (N2O) or nitrogen monoxide (NO) and carbon disulfide (CS2). Ignition of the mixture in a long tube results in a bright blue chemiluminescent flash, accompanied by a characteristic barking or woofing sound.
What is happening in this demonstration is a redox reaction where the oxidant is the CS2 and the reducing agent is the NO or N2O. The reaction releases a lot of gas (N2, CO2, SO2), which produces the woofing sound, elemental sulphur (S8) which leaves a yellow layer covering all the tube inner part, and a lot of energy (bright blue chemiluminescent flash).
4 NO + CS2 -> 2 N2 + CO2 + SO2 + 1/8 S8
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