about mole concept..

Asked by  | 19th Mar, 2013, 04:25: AM

Expert Answer:

Mole is basically a unit. It is the SI unit of amount of substance.

It is used for the measurement of very small, microscopic particles such as atoms and molecules.

Broadly speaking, it is used to measure the number of particles –whether atoms or molecules present in a given amount of substance.

One mole is the amount of substance that contains as many particles as there are atoms present in exactly 12g of 12C isotope off Carbon. It has been found that there are 6.023 X 1023 atoms present in 12 g of 12C isotope of Carbon.

  1. One mole of any substance will always contain 6.023 X 1023 particles, no matter what the substance is. Therefore 1 mole of Na atoms contains 6.023 X 1023 atoms of Na, 1 mole of Hydrogen atom contains 6.023 X 1023 atoms of Hydrogen atom, 1 mole of Hydrogen molecule will contain 6.023 X 1023 molecules of Hydrogen molecule (H2), 1 mole of CO2 will contain 6.023 X 1023 molecules of H2O.
  2. One mole of any substance is always equal to its molar mass in grams. We know that the molar mass of a substance in grams is always equal to the atomic mass (for atoms) or molecular mass (for molecules).
    Therefore 1 mole of Na atoms = molar mass of Na atoms = 23 g.
    1 mole of H2O molecules = molar mass of H2O molecules = 18.02 g

Answered by  | 19th Mar, 2013, 05:55: AM

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