mole concepts jee advanced

📘 Mole Concept – Complete Notes (JEE Main, Advanced & Olympiad Level)




🔹 1. What is a Mole? (Basic Theory)

• A mole is the SI unit of the amount of substance.
• 1 mole = 6.022 × 10²³ particles (Avogadro’s number)
• These particles can be atoms, molecules, ions, or electrons.

Examples: - 1 mole of Na = 6.022×10²³ Na atoms - 1 mole of O₂ = 6.022×10²³ molecules of O₂




🔹 2. Molar Mass

• Molar mass = Mass of one mole of a substance (g/mol)
• Equal to the relative atomic/molecular mass but expressed in grams

Examples: - H₂O = 2×1 + 16 = 18 g/mol - CO₂ = 12 + 2×16 = 44 g/mol




🔹 3. Core Formulas

1. Number of moles (n):

Given mass
n=
Molar mass
Number of particles
n=
6.022 × 1023
Volume at STP
n=
22.4 L

2. Number of particles:


Particles = n × 6.022 × 1023

3. Mass of one particle:

Molar mass
Mass of 1 particle =
6.022 × 1023

4. Molar volume at STP:


5. 1 mole of any gas at STP occupies 22.4 L




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