المراجعة النهائية فى مادة الكيمياء لغات - الجزء الرابع

المراجعة النهائية فى مادة الكيمياء لغات - الجزء الرابع



Reduction.
The process of gaining electrons associated with decreasing oxidation number

Octet rule.
By the exception of H2, Li and Be atoms of all elements tend to reach octet structure.

Molecular orbital theory.
All the atomic orbitals of combined atoms are mixed or hybridized forming molecular orbitals

Hybridization
Overlap two or more orbitals close in energy to form hybrid orbitals similar in energy in the same atom

Metallic bond
The valence electrons of a metal forming electron cloud which decrease the repulsion between the +ve ions of the metal

Photoelectric phenomenon.
Some atoms such as K and Cs when they are exposed to light their free electrons move forming electric current

Allotropy
Presence of an element in more than one form different in physical properties but similar in chemical ones

Passivity
Formation of non porous layer of oxide, surround the metal and stop further reaction

Iron ore dressing
Preparing iron ore to be reduced in the furnaces by get rid of humidity and increases the percentage of iron in the ore

Pig iron
Iron result from blast furnace which contains 95% iron, 4% carbon and 1% impurities (such as Mn, Si, P and S)

Quantitative analysis
Determination of the concentration or quantity of the constituents of the sample

Avogadro's law
Equals volumes of under the same pressure and temperature contains equal numbers of molecules

Indicators
Substance which change their colours in the reaction medium so they can used to detect the end point at which complete reaction takes place

Gay-Lussac's law
The volume of gases involved in reaction and the gases produced are exist in fixed ratio

Ostwald's law
At a constant temperature, the degree of ionization (α) increases by dilution

Ionic product of water
The resultant of multiplying the concentration of hydrogen ion[H+] times that of hydroxyl ion[OH-] , its =10-14mol/liter

Catalyst
A substance that causes a change in the rate of the chemical reaction without it self being changed

Le Chatelier's principle
Change in any of the conditions of a chemical equilibrium such as concentration, pressure or temperature cause shift of the equilibrium in the direction which will oppose this change

Electrolytic cell
Kind of electric cells in which the energy from external source is used to make spontaneous oxidation reaction to occur

Faraday's second law
The masses of different materials formed or consumed by the same amount of electricity are directly proportional to their equivalent masses

Faraday
The quantity of electricity required to precipitate or dissolve equivalent mass in grams of any element during electrolysis

Electromotive force
The sum of oxidation and reduction potentials for the two half cells

Elimination reaction:
Reaction of methane with halogen in the direct sunlight to form carbon and hydrogen halide

Catalytic hydration reaction:
Adding water in presence of catalyst

Thermal catalytic cracking
Big molecule is converted into small molecules in presence of heat and catalyst

Friedel craft(Alkylation)
Alkayl group replaces hydrogen in benzene ring forming toluene

Bayer's reaction
Oxidation of alkene in presence of alkaline KMnO4 to form glycol

Markownikoff's rule:
On adding asymmetrical reagent to asymmetrical alkene the positive part of the reagent is attached to carbon atom has big no. of hydrogen

Biological method:
Oxidation of dil solution of ethanol by atmospheric oxygen in presence of vinegar bacteria to form acetic acid

Alcoholic fermentation:
Alcoholic fermentation of starch or sugar by adding yeast to form ethanol

Catalytic reforming
Normal hexane is converted into benzene in presence of heat and catalyst

Alkaline hydrolysis
Heating alkyli halide in presence of alkali to form alcohol