شرح درس
Solutions
CHEMISTRY - Secondary 1
In This part we will study
Second According to the ability to conduct electricity:
Solutions of substances are divided into two types according to the ability to conduct electricity.
Solutions are divided into
Electrolytes: are substances which their solutions or molten can conduct electricity by the free ions movement.
Strong electrolytes
Strong electrolytes: are substances which are completely ionized and strongly conduct electricity.

1. Ionic compounds like: Sodium chloride NaCl and sodium hydroxide NaOH, which are completely dissociated into ions when they dissolve in water.

2. Polar covalent compounds like :
Hydrogen chloride HCl, which is completely ionized when it dissolves in water.

Weak electrolytes
Weak electrolytes: They are substances which are partially ionized and weakly conduct electricity.
- Ammonium hydroxide NH4OH
- Acetic acid CH3COOH

* All organic acids are weak electrolytes.
* Solid salts as NaCl(s) do not conduct electricity, while when they dissolve in water
(i.e. being in aqueous solution form) as NaCl(aq) they conduct electricity.
*All gases - at normal conditions of temperature and pressure - do not conduct electricity.

Hydrogen chloride gas HCl(g) does not conduct electricity, while when it dissolves in water it forms hydrochloric acid HCl(aq) which is a good electric conductor, this dissolving process is represented by the following equation :



where H+ ions binds with water molecules forming hydronium ions H3O(aq) (hydrated protons).
H2O(l) + H+(aq) → H3O+(aq)

B- Non-electrolytes
Nonelectrolytes: are substances which their solutions or moltens can't conduct electricity, as they have no free ions or hydrated ions .
Examples
* Ethyl alcohol. * Sugar solution.
Hydrogen peroxide which is known commercially in Egypt as oxygen water is a nonelectrolyte

According to the degree of Saturation:

Solutions are divided into

Unsaturated solution: is the solution which contains less amount of solute and can accept more amount of solute at a certain temperature
Saturated solution: is the solution which contains the maximum amount of solute at a certain temperature.
Supersaturated solution: is the solution that accepts more amount of solute substance after reaching the state of saturation.
It is possible to convert:
 Saturated solution to supersaturated solution, by heating the saturated solution and adding more solute to it.
 Unsaturated solution to saturated solution, by two methods, which are:
a. Cooling: Cool the supersaturated solution and leave it for a short time, the excess solute will be separated (precipitate) from the solution.

b. Crystallization: Put small crystals from the solute in the supersaturated solution and leave it for a short time, the solute molecules will be precipitated as crystals on the surface of the seeding crystals.

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