Mole Concept Basics - Physics Wallah - Free Printable

The image you've uploaded presents a conceptual diagram that illustrates the mole concept in chemistry, showing how one mole of a substance relates to particles (atoms, molecules) and mass (gram atom, gram mole, gram formula mass).

Let’s break it down and explain each part:

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🔷 Central Concept: 1 Mole

At the center is "1 Mole", which is the fundamental unit used in chemistry to count particles (atoms, molecules, ions, etc.) in a convenient way.

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🔷 In Terms of Particles

From the central "1 Mole", two branches go upward:

- Left:
→ 6.023 × 10²³ atoms (Nₐ atoms)
This refers to Avogadro's number (Nₐ) — the number of atoms in one mole of an element.

- Right:
→ 6.023 × 10²³ molecules (Nₐ molecules)
This means one mole of a molecular substance contains Avogadro's number of molecules.

✔ So, 1 mole = 6.023 × 10²³ particles (either atoms or molecules depending on the substance).

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🔷 In Terms of Mass

From the central "1 Mole", three branches go downward:

1. 1 gram atom of element
→ This means the atomic mass of an element expressed in grams.
Example:
- 1 gram atom of carbon = 12 grams (since atomic mass of C = 12 g/mol)
- This is the mass of 1 mole of atoms of that element.

2. 1 gram mole of substance
→ This is the molar mass of a substance (in grams per mole).
Example:
- 1 gram mole of water (H₂O) = 18 grams (molar mass = 18 g/mol)

3. 1 gram formula mass of substance
→ Used for ionic compounds (e.g., NaCl).
Example:
- Gram formula mass of NaCl = 58.5 g (Na = 23, Cl = 35.5)
→ This is the mass of 1 mole of formula units.

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✔ Summary of Key Concepts

| Term | Meaning |
|------|--------|
| 1 mole | A quantity containing 6.023 × 10²³ particles |
| Avogadro's number (Nₐ) | 6.023 × 10²³ particles/mol |
| Gram atom | Mass of 1 mole of atoms of an element |
| Gram mole | Mass of 1 mole of molecules of a substance |
| Gram formula mass | Mass of 1 mole of formula units (for ionic compounds) |

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🧠 Example to Clarify:

Let’s take oxygen (O₂):

- 1 mole of O₂ = 6.023 × 10²³ molecules of O₂
- 1 mole of O₂ = 32 grams (molar mass = 32 g/mol)
- So, 32 grams of O₂ contains 6.023 × 10²³ molecules

For iron (Fe):

- 1 mole of Fe = 6.023 × 10²³ atoms
- 1 mole of Fe = 56 grams (gram atom of iron)

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✔ Final Answer:

This diagram shows that:

> One mole of any substance contains:
> - 6.023 × 10²³ particles (atoms or molecules), and
> - Has a mass equal to its atomic/molecular/formula mass in grams.

Thus, the mole bridges the microscopic world (particles) with the macroscopic world (measurable mass).

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📌 Conclusion:

The diagram effectively summarizes the mole concept by linking:
- Particles (via Avogadro’s number),
- Mass (via gram atom, gram mole, gram formula mass),
- And the central idea of 1 mole as a bridge between them.

This is essential for stoichiometry, chemical calculations, and understanding reaction proportions.