Chemical substance facts for kids

Water and steam are two different forms of the same chemical substance

A chemical substance is any material with a known chemical composition. For example, water has the same properties and the same ratio of hydrogen to oxygen whether it came from a river or was made in a laboratory. Typical chemical substances found in the home include water, salt (sodium chloride) and bleach. Generally, substances exist as a solid, a liquid, or a gas, and may change between these phases of matter when there are changes in temperature or pressure.

Chemical elements

Native sulfur crystals. Sulfur occurs naturally as elemental sulfur, in sulfide and sulfate minerals and in hydrogen sulfide.

An element is a chemical substance that is made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmutated into another element through a nuclear reaction. This is so, because all of the atoms in a sample of an element have the same number of protons, though they may be different isotopes, with differing numbers of neutrons.

As of 2012, there are 118 known elements, about 80 of which are stable – that is, they do not change by radioactive decay into other elements.

Gallery

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  Gray silicon powder, an element. All the other ones are chemical compounds.

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  White sodium chloride

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  Pink hydrated (with water) manganese(II) chloride

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  Brown manganese(II) carbonate

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  Black copper(II) oxide

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  Red hydrated (with water) cobalt(II) chloride

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  Orange potassium dichromate

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  Yellow sodium chromate

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  Green hydrated (with water) copper(II) chloride

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  Blue hydrated (with water) copper(II) sulfate

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  Purple anhydrous (without water) chromium(III) chloride

Images for kids

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  Colors of a single chemical (Nile red) in different solvents, under visible and UV light, showing how the chemical interacts dynamically with its solvent environment.

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  Potassium ferricyanide is a compound of potassium, iron, carbon and nitrogen; although it contains cyanide anions, it does not release them and is nontoxic.

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  Cranberry glass, while appearing homogeneous, is a mixture consisting of glass and gold colloidal particles of about 40 nm in diameter, giving it a red color.

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  Chemicals in graduated cylinders and beaker.

See also

In Spanish: Sustancia química para niños