"Mole is the SI unit used to measure the amount of substance. Define it and provide examples."

 The Mole (Mole) as an SI Unit

The mole is primarily used as an SI unit to measure the amount of substance. It is a standard unit that allows us to quantify the number of particles (atoms, molecules, ions, or particles) in any given material.

Definition of Mole:

The mole is defined as: "A mole is the amount of any substance that contains exactly 6.022 × 10²³ elementary particles (particles)." These elementary particles can be atoms, molecules, ions, or electrons.

Alternative Definition: A mole is the amount of a substance whose mass is equal to its molar mass, and this mass is measured in grams.

Examples of Mole:

1. For Atoms: One mole of carbon (C) atoms has a mass of 12 grams. This means that 12 grams of carbon contains 6.022 × 10²³ carbon atoms.

2. For Molecules: One mole of water (H₂O) molecules has a mass of 18 grams. This means that 18 grams of water contains 6.022 × 10²³ water molecules.

3. For Ions: One mole of sodium chloride (NaCl) has a mass of 58.5 grams. This means that it contains 6.022 × 10²³ Na⁺ ions and 6.022 × 10²³ Cl⁻ ions.

Practical Use of Mole: The concept of the mole is used in chemistry for reactions and stoich.