Final answer:
Avogadro's number is the number of entities composing a mole and is 6.022 × 10²³. It is used in chemistry to convert between the mass of a sample and the number of atoms or molecules present.
Step-by-step explanation:
Avogadro's number, also known as the Avogadro constant, is the number of entities composing a mole and has been experimentally determined to be 6.022 × 10²³. It is a fundamental constant in chemistry and is used to convert between the mass of a sample and the number of atoms or molecules present. For example, if you have one mole of carbon atoms, it would contain 6.022 × 10²³ carbon atoms.