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The Mole
CHEMISTRY - Secondary 1
In This part we will study
Molecule: is the smallest fundamental part of matter which can exist solely, and retain
the properties of this matter.
Atom : is the smallest building unit of matter which participates in chemical reactions.

Ionic compounds exist in the form of a regular geometrical structure known as the crystal lattice, as each ion is surrounded by opposing ions
(in terms of charge) from all directions.

It is difficult practically to deal with the atom, the molecule or the formula unit in chemical calculations, as they are extremely small particles where their dimensions are estimated in nano scale.
The Mole
It represents the amounts of chemical substances in the international system of units (SI), where it is equivalent to the amount of a substance which contains the same number of units (atoms, ions, molecules or formula units) that exist in 12 g of carbon-12 ((_"6" ^"12" )"C" )

The formula unit and the mole of lead (II) chloride.

Example (1):
 Calculate the number of atoms of the elements which compose the formula unit of calcium phosphate, and the number of moles (mol) of atoms of the elements which compose a mole of it.
Solution: Calcium phosphate is an ionic compound, its chemical formula is Ca3(PO4)2

Example (2) :
Conclude the number of moles of each of:
- Magnesium chloride formula units.
- Sulphate anions .
In a mixture of magnesium chloride and magnesium sulphate contains :
4 mol Cl- , 3 mol Mg2+

Best wishes to you
Mr.Ahmed Elbasha

كيمياء الصف الاول الثانوي لغات - الفصل الدراسي الاول
شرح كيمياء لغات اولي ثانوي - مستر احمد الباشا
كيمياء لغات - الصف الاول الثانوي - كيمياء اولي ثانوي الترم الاول - كيمستري اولي ثانوي الترم الاول