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Rubber is a material, which can stretch and shrink. It is a polymer. It can be produced from natural sources or can be synthesised on an industrial scale. Many things are made from rubber, like gloves, tires, plugs, and masks. A few things can be ...

Thermosetting polymer

A thermosetting plastic, also known as a thermoset, is polymer material that irreversibly cures. The curing may be done by: heat) a chemical reaction irradiation such as electron beam processing Thermoset materials are usually liquid or malleable ...

Potassium carbonate

Potassium carbonate, also known as potash or pearl ash, is a chemical compound. It is made of potassium and carbonate ions. Its chemical formula is K 2 CO 3.

Potassium hydroxide

It is a white powder. It dissolves easily in water to make a basic solution. It is corrosive to skin. It reacts with acids to give potassium salts. It is less common than sodium hydroxide. About 700.000 tons are made each year. It is hygroscopic, ...

Potassium sulfide

Potassium sulfide is a chemical compound. Its chemical formula is K 2 S. It contains potassium and sulfide ions. The potassium is in its +1 oxidation state.

Selenium dioxide

Selenium dioxide, also known as selenious oxide, selenous oxide, or selenium oxide, is a chemical compound. Its chemical formula is SeO 2. It contains selenium in its +4 oxidation state. It also contains oxide ions. It is toxic.

Sodium hydroxide

Sodium hydroxide is an alkali which is also known as caustic soda. Caustic means "burning" and caustic soda takes its name from the way it can burn the skin. It has the chemical formula of NaOH. It is a base, meaning it has a high pH. It is the m ...

Sodium tellurite

Sodium tellurite is a colorless solid. The tellurite ion can react with water to make sodium hydrogen tellurite, NaHTeO 3. It dissolves in water easily. It is a weak oxidizing agent can be reduced to tellurium and a weak reducing agent can be oxi ...

Carbon disulfide

Carbon disulfide, also known as carbon bisulfide, is a chemical compound. It consists of carbon and sulfide ions. It contains carbon in its +4 oxidation state and sulfur in its -2 oxidation state. Its chemical formula is CS 2.

Hydrogen sulfide

Hydrogen sulfide is the chemical compound with the formula H 2 S, is a colorless, toxic, flammable gas that is responsible for the foul smell of rotten eggs and flatulence. It often results when bacteria break down organic matter if there is no o ...

Thallium(I) sulfate

Thallium sulfate, also known as thallous sulfate, is a chemical compound. Its chemical formula is Tl 2 SO 4. It has thallium and sulfate ions in it. The thallium is in its +1 oxidation state.

Thallium(I) sulfide

Thallium sulfide, also known as thallous sulfide, is a chemical compound. Its chemical formula is Tl 2 S. It has thallium and sulfide ions in it. The thallium is in its +1 oxidation state.

Zinc sulfide

Zinc sulfide is white when pure. It does not dissolve in water. It can burn at a high temperature to make sulfur dioxide and zinc oxide. It reacts with strong acids to make hydrogen sulfide.

Cadmium telluride

Cadmium telluride is a black solid. It reacts with acids to make toxic cadmium compounds and toxic hydrogen telluride gas. It does not dissolve in water.

Tellurium(IV) bromide

Tellurium bromide, also known as tellurium tetrabromide, is a chemical compound. Its chemical formula is TeBr 4. It contains tellurium and bromide ions. The tellurium is in the +4 oxidation state.

Tellurium(IV) oxide

Tellurium oxide, also known as tellurium dioxide, is a chemical compound. Its chemical formula is TeO 2. It contains tellurium in its +4 oxidation state. It also contains oxide ions.

Thallium(I) carbonate

Thallium carbonate, also known as thallous carbonate, is a chemical compound. Its chemical formula is Tl 2 CO 3. It has thallium and carbonate ions in it. The thallium is in its +1 oxidation state.

Thallium(I) hydroxide

Thallium hydroxide, also known as thallous hydroxide, is a chemical compound. Its chemical formula is TlOH. It has thallium and hydroxide ions in it. The thallium is in its +1 oxidation state.

Thallium(III) oxide

Thallium oxide, also known as thallic oxide, is a chemical compound. Its chemical formula is Tl 2 O 3. It has thallium and oxide ions in it. The thallium is in its +3 oxidation state.


Polycarbonate is a transparent thermoplastic. This material is tough and stable. It can resist a high temperature of 138°C and a low temperature of -40°C. It is stain resistant and non-toxic. The weight of polycarbonate is one sixth of glass. Ind ...

Tin(II) oxide

Tin oxide, also known as stannous oxide, is a chemical compound. Its chemical formula is SnO. It has tin in an oxidation state of +2. It also has oxide ions in it.

Tin(IV) oxide

Tin oxide, also known as tin dioxide or stannic oxide is a chemical compound. Its chemical formula is SnO 2. It has tin and oxide ions in it. It has tin in its +4 oxidation state.


Toxicity is the degree to which a substance can damage an organism. It is the subject-matter of toxicology. A central idea in toxicology is that almost everything is toxic when taken to excess. Effects are dose-dependent: even water can lead to w ...

Carbon monoxide

Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. It consists of one carbon atom covalently bonded to one oxygen atom. It is made when carbon compounds burn and there is not enough oxygen. It is a good fu ...

Exposure (toxicology)

Toxic exposure means that a toxin touched or got into a persons body. That person has been exposed to the toxin. After a person is exposed to a toxin, many different things about that person, the toxin, and the exposure affect toxicity. Toxicity ...

Zinc hydroxide

Zinc hydroxide is a white solid. It does not dissolve in water. It reacts with acids to make zinc salts. It dissolves in concentrated bases. It dissolves in ammonia to make a colorless solution. It can be heated to make zinc oxide.

Zinc oxide

Zinc oxide is a white solid. It does not dissolve in water. It reacts with acids to make zinc salts. It can react with water to make zinc hydroxide. It reacts with phosphoric acid to make zinc phosphate, a cement. It reacts with hydrogen sulfide ...

Allotropes of carbon

There are several allotropes of carbon. Diamond and graphite are the most famous. Graphite is a conductor, a semimetal. It can be used, for instance, as the material in the electrodes of an electrical arc lamp. Graphite is the most stable form of ...


Carbon is a very important chemical element, with a chemical symbol of C. All known life on Earth needs it. Carbon has atomic mass 12 and atomic number 6. It is a nonmetal, meaning that it is not a metal. When iron is alloyed with carbon, hard st ...


A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called ca ...


Graphene is one of the forms of carbon. Like diamonds and graphite, the forms of carbon have different crystal structures, and this gives them different properties. Graphene is the basic 2D form of a number of 3D allotropes, such as graphite, cha ...


Graphite, like diamond, is an allotrope of carbon. They are very similar to each other but the different structures of the molecule affect the chemical and physical properties. Graphite is made of layers of carbon atoms. These layers can slide ov ...


Fluorine is a chemical element that is very poisonous. Its atomic number is 9, and its atomic mass is 19. It is part of the Group 7 on the periodic table of elements.

Hydrogen ion

Hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, there are two types: positively charged ions and negatively charged ions.

Isotopes of hydrogen

Hydrogen has three main isotopes, protium, deuterium and tritium. These isotopes form naturally in nature. Protium and deuterium are stable. Tritium is radioactive and has a half-life of about 12 years. Scientists have created four other hydrogen ...


Some chemical elements are called metals. They are the majority of elements in the periodic table. These elements usually have the following properties: They can conduct electricity and heat. They have a high melting point. They have a shiny appe ...

Arc welding

Arc welding is the most effective way of permanently joining metals. It melts the two metals being joined and fuses them together, effectively turning them into one solid unit. Arc welding uses electricity to melt the metals and the welding fille ...


Bullion refers to coins, jewellery and bars made of a precious metal such as gold or silver, that are bought and stored simply as an investment in the prices of the metal they are made of. Unlike numismatic coins, a bullion coin is a coin, new or ...

Metal leaf

Metal leaf is a type of metallic foil used mostly for decoration. Gold leaf, a thin layering of gold foil, is the most common form of metal leaf, and the two words are often mixed up. Only very malleable metals can be made into leaf. Those metals ...

Oxfordshire Ironstone Railway

The Oxfordshire Ironstone Railway was a standard gauge railway that served an ironstone quarry near the village of Wroxton in Oxfordshire. It linked to the Great Western Railway about 6 kilometres to the east, just north of the town of Banbury. B ...

Tin foil

Tin foil is a thin foil made of tin. Tin foil was replaced after World War II by aluminium foil. In the late 19th century and early 20th century, tin foil was in commonly used.


Oxygen is a chemical element. It has the symbol O and atomic number 8. It is the third most common element in the universe, after hydrogen and helium. Oxygen is more than a fifth of the Earths atmosphere by volume. In the air, two oxygen atoms us ...


Antimony is a chemical element. It has the chemical symbol Sb. The symbol Sb is from the Latin name of stibium for the element. It has the atomic number 51. Its atomic mass is 121.8. It is a blue-gray element that is somewhat toxic.


Arsenic is chemical element 33 on the periodic table. Its symbol is As. Its atomic number is 33 and its atomic mass is 74.92. It is in the pnictogen group on the periodic table.


A metalloid or semimetal is a chemical element. Metalloids are elements that have the properties of both metal and non-metal elements. It might be shiny, but brittle. It might be dull, but conducts electricity. The most common semimetal is silico ...


Silicon is a chemical element. Its atomic number is 14 on the periodic table. Its symbol is Si. It is a hard, brittle crystalline solid. It is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table. Silicon lo ...


Tellurium is a chemical element. It has the chemical symbol Te and the atomic number 52. It has 52 protons and 52 electrons. Its mass number is 127.6. It has 8 natural isotopes. 4 are stable and 4 are radioactive. One of the radioactive ones last ...

Addition reaction

In organic chemistry an addition reaction happens when two molecules come together to make a bigger one. This can only happen when one of the molecules already has a double or triple bond. These can be carbon-carbon bonds or even carbon-oxygen, c ...

Chemical kinetics

Chemical kinetics, also called reaction kinetics, is studying how fast chemical reactions go. This includes studying how different conditions such as temperature, pressure or solvent used affect the speed of a reaction. Chemical kinetics can also ...


Chemiluminescence is a kind of luminescence. It is a process of making light from a chemical reaction. Chemiluminescence in biological systems is called bioluminescence. The light made in chemiluminiscence is not directly related to heat. A simpl ...

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