There are 6.022 x 10²³ particles present in 1 mol of a pure substance. This number is known as Avogadro's number.

It's important to note that the type of particle depends on the substance:

* For atoms: 1 mol of a substance contains 6.022 x 10²³ atoms.

* For molecules: 1 mol of a substance contains 6.022 x 10²³ molecules.

* For ions: 1 mol of a substance contains 6.022 x 10²³ ions.