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What role does the Mole concept play in Chemistry, particularly in relation to Molecular Mass?
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- Development of Mole Concept: From ‘Heap’ to Fundamental Unit in Chemistry: The word “mole” was introduced around 1896 by Wilhelm Ostwald who derived the term from the Latin word moles meaning a ‘heap’ or ‘pile’.
- A substance may be considered as a heap of atoms or molecules.
- In 1967, the unit mole was accepted to provide a simple way of reporting a large number.
- Understanding Concept: Bridging Quantities and Mass in Chemistry: One mole of any species (atoms, molecules, ions or particles) is that quantity in number having a mass equal to its atomic or molecular mass in grams.
- The mole, symbol mol, is the SI unit of amount of substance.
- Avogadro Constant: Magnitude of Mole-Particle Relationships in Chemistry The number of particles (atoms, molecules or ions) present in 1 mole of any substance is fixed, with a value of 6.02214076 x 1023.
- This number is called the Avogadro Constant or Avogadro Number (represented by N0), named in honor of the Italian scientist, Amedeo Avogadro.
- 1 mole (of anything) = 6.02214076 x 1023 in number = Relative mass in grams
- Relativity in Chemistry: Connecting Mole and Molecular Mass: The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams.
- Atomic Mass: Weight of Individual Atoms: The atomic mass of an element gives us the mass of one atom of that element in atomic mass units (u).
- Gram Atomic Mass: Link Between Atomic and Molar Mass in Chemistry: Mass of 1 mole of an atom of that element, that is, molar mass is also known as gram atomic mass.
- Example: Atomic mass of oxygen =16u. So, gram atomic mass of oxygen = 16 g.
- 16 u oxygen has only 1 atom of oxygen, 16 g oxygen has 1 mole atom, that is, 6.022×1023 atoms of oxygen.
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