One mole of any substance contains how many entities?

• A. 6.022x10^24 entities
• B. 6.022x10^23 entities
• C. 1.0x10^23 entities
• D. 6.022x10^22 entities

Answer: (B)

One mole is a counting unit that ties the amount of substance to a fixed number of particles. This fixed number is Avogadro’s constant, 6.022 × 10^23. So one mole of any substance contains 6.022 × 10^23 entities, whether you’re counting atoms, molecules, or formula units. This constant is what lets us convert between mass and particle count: for example, 1 mole of carbon has 6.022 × 10^23 carbon atoms, and 1 mole of water has 6.022 × 10^23 water molecules. The other figures are simply different powers of ten and do not define a mole.