What is Avogadro's constant and how is it used in GCSE calculations?

• A. 6.02 x 10^25 particles per mole; used to convert between moles and volume.
• B. 6.02 x 10^23 kilograms per mole.
• C. 6.02 x 10^23 particles per mole; used to convert between moles and number of particles.
• D. 6.02 x 10^23 liters per mole.

Answer: (C)

Avogadro's constant is the number of particles in one mole, 6.02 × 10^23 particles per mole. It acts as a bridge between the macroscopic amount of substance and the microscopic count of particles. So, if you have n moles, the number of particles is N = n × 6.02 × 10^23; if you know N, the moles are n = N ÷ (6.02 × 10^23). This is the standard way GCSE problems count atoms or molecules. The other statements misplace the idea: kilograms per mole would describe molar mass, liters per mole would describe molar volume, and Avogadro’s number isn’t a direct volume converter.