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    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
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10. Mole Concept

Definitions
  • Relative atomic mass, Ar: The relative atomic mass of an atom is the average mass of an atom of an element compared to 1/12 the mass of an atom of carbon-12.
  • Relative molecular mass, Mr: The relative molecular mass of a molecule is the average mass of one molecule of a compound compared to 1/12 the mass of an atom of carbon-12.
  • Empirical formula: Simplest formula showing the ratio of the atoms of each element in one molecule of a compound.
  • Molecular formula: The formula showing the actual number of the atoms of each element in one molecule of a compound.

State Symbols
  • s – solid (e.g. solid copper(II) chloride contains Cu2+ and Cl- ions in fixed positions)
  • l – liquid / molten (e.g. liquid/molten copper(II) chloride contains only mobile Cu2+ and Cl- ions)
  • g – gas ( i.e. carbon dioxide molecules which are far apart and in rapid, random movement)
  • aq – aqueous (i.e copper(II) chloride solution contains Cu2+, Cl-, H+, OH-)

Tips for calculation:
  • Ar - from Periodic Table
  • Mr - sum of Ar in formula
  • Mr (no units) is numerically equal to molar mass  (g/mol)
  • For gases only, mole ratio is equivalent to volume ratio. One mole of any gas occupies the same volume (24 dm3).
  • Calculation on concentration of solutions: The concentration of a solution gives the amount of solute in 1 dm3 of solution. It can be expressed in g/cm3 or mol/dm3.


Formulae for Calculations
Click here to download a FREE Formula Sheet for Mole Calculation.

Limiting Reactants
  •  A balanced chemical equation is used to calculate the exact amount of reactants used up and products formed using its mole ratio.
  • The reactant that is completely used up is known as the limiting reactant. It determines or limits the amount of product formed.
  • Once the limiting reactant is used up, the reaction stops.
  • Always use the limiting reactant to calculate the product.
Next: Electrolysis
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  • Home
  • More Information
  • Contact Me
  • Blog
  • FREE 5-MIN Notes
    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
  • Free Printables