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  1. Glossary
  2. /Chemistry
  3. /Mole

What is Mole?

In short

A mole is the amount of a substance that contains 6.022×10236.022 \times 10^{23}6.022×1023 particles, which may be atoms, molecules or ions. This number is the Avogadro constant.

In simple words

The mole lets chemists count particles by weighing them. The mass of one mole in grams equals the relative formula mass. So one mole of carbon-12 has a mass of exactly 12 g12\ \text{g}12 g. The number of moles is n=massmolar massn = \dfrac{\text{mass}}{\text{molar mass}}n=molar massmass​. For a gas at 273 K273\ \text{K}273 K and 1 atm1\ \text{atm}1 atm, one mole occupies about 22.4 L22.4\ \text{L}22.4 L.

Example

The molar mass of water is 18 g/mol18\ \text{g/mol}18 g/mol. A sample of 9.0 g9.0\ \text{g}9.0 g of water is 9.0 g18 g/mol=0.50 mol\dfrac{9.0\ \text{g}}{18\ \text{g/mol}} = 0.50\ \text{mol}18 g/mol9.0 g​=0.50 mol, which has 0.50×6.022×1023=3.0×10230.50 \times 6.022 \times 10^{23} = 3.0 \times 10^{23}0.50×6.022×1023=3.0×1023 molecules.

Also searched as: mole number, avogadro constant.

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Related terms

  • Molecular Mass
  • Law of Constant Proportions

← All glossary terms

Learn it in

  1. Molecular Mass and the MoleClass 9 to 10
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Practise

  1. An acid found in sour milk contains only carbon, hydrogen and oxygen…Advanced
  2. An organic compound contains only carbon, hydrogen, nitrogen and oxygen…Hard
  3. Gold has a molar mass of 196.97 g mol⁻¹…Hard
  4. A stick of chalk is 10.0 g of calcium carbonate, CaCO₃, of molar mass 100.09 g mol⁻¹…Medium
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Quick questions

  1. Match each sample in List-I with the amount of oxygen atoms it contains in List-II.…Hard
  2. An element X forms a volatile chloride that contains 83.5% chlorine by mass. At the same…Advanced
  3. Read these statements about amounts of substance. Atomic masses in g mol⁻¹: H 1, C 12, N…Hard

More Chemistry terms

  1. Acids, Bases and pH
  2. Alkane (Saturated Hydrocarbon)
  3. Allotrope
  4. Atom
  5. Bohr Model of the Atom
  6. Catalyst
All Chemistry terms →

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