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CAS registry number facts for kids

Kids Encyclopedia Facts

A CAS registry number is like a special ID number for every different chemical substance. It's given out by a group called the Chemical Abstracts Service (CAS). You might also hear it called a CASRN or CAS number. These numbers help scientists around the world identify chemicals easily.

CAS numbers are unique. They are given to many types of substances. This includes organic chemicals (like sugar) and inorganic ones (like salt). They also identify minerals, isotopes (different forms of an element), and alloys (mixtures of metals).

A CAS number always ends with a special check digit. This digit helps to make sure the number is correct. The numbers do not tell you anything about what the chemical looks like or how it is built. They are just for identification.

What is a CAS Number?

The Chemical Abstracts Service has identified over 164 million different organic and inorganic substances. They have also identified 68 million protein and DNA sequences. About 15,000 new substances are added to their list every day. This makes the CAS registry number a very important tool for science.

Images for kids

  • Cascommonchemistry2022

    Screenshot of the CAS Common Chemistry database with information about caffeine (58-08-2).

See also

Kids robot.svg In Spanish: Número de registro CAS para niños

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