📘 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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🔹 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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