What does cas mean? in chemistry
The CAS or CAS Number, also known as the CAS Registration Number, is a registration number developed by the Chemical Abstracts Service (CAS) for chemical substances. This number is an important tool for retrieving information on chemical substances with multiple names. It is a unique digital identification number for a substance (compound, polymer material, biological sequences), mixture or alloy.
CAS number format: A CAS number is divided into three parts by a hyphen "-". The first part has 2 to 7 digits, the second part has 2 digits, and the third part has 1 digit as the check code. The CAS numbers are arranged in ascending order and do not have any intrinsic meaning. The check code is calculated as follows: the last digit of the CAS sequence number (the first and second digits) is multiplied by 1, the last second digit is multiplied by 2, and so on, and then all the products are added, and then the sum is divided by 10. The remainder is the check code of the third part. For example, if the first two parts of the CAS number of water (H2O) are 7732-18, then its check code = (8 × 1 + 1 × 2 + 2 × 3 + 3 × 4 + 7 × 5 + 7 × 6) mod 10 = 105 mod 10 = 5. (mod is the remainder operator)
