نتيجة امتحانات 2011 Headline Animator

sharing

الثلاثاء، 26 مارس، 2013

كيمياء لغات - الباب الثانى | Strength of oxygenated acids


الصف الثالث الثانوى كيمياء لغات الباب الثانى| كيمياء لغات
كيمياء لغات - الباب الثانى | Strength of oxygenated acids


01 Strength of Oxygenated Acids



الدرس في شكل نص مقروء

كيمياء لغات - الباب الثانى | Strength of oxygenated acids
Strength of oxygenated acids
*It depends on the number of Oxygen atoms which does not bind with
Hydrogen atoms
*Oxygenated acid have the formula MOn (OH)m
M atom of an element
On atoms of Oxygen which do not bind with Hydrogen atom
m number of oxygen bind with hydrogen
Acid
MOn (OH)m Oxygen atoms which not bind with Hydrogen Strength of acid Chemical formula
Si (OH)4
ortho siliconic _____ weak acid H4SiO4
PO (OH)3
orthophosphoric 1 moderate H3PO4
SO2 (OH)2
Sulphuric 2 strong H2SO4
ClO3 (OH)
Perochloric 3 very strong HClO4
G.R.F 1-Perochloric acid HClO4 more stronger than orthophosphoric acid.
2- Perochloric acid more stronger than sulphuric acid. Exam 2012
3- HClO4 is stronger than H4SiO4 [ orthosiliconic acid]
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
4- Strength of oxygenated acids increases from left to right across the period.
………………………………………………………………………….....................
7) Graduation of oxidation number in the periodic table.
* The old definition of valence: -
Number of hydrogen atoms which combines with one atom of element.
Number of hydrogen atoms that can be replaced by one atom of element.
Ex. HF H2O NH3
(Flourine is monovalent) (Oxygen is divalent) (Nitrogen is trivalent)
* The modern definition of valence: -
Number of ( unpaired ) electrons in the valence shell of an atom.
7N 1S2 , 2S2 , 2P3 Nitrogen is trivalent because
It has three unpaired electrons G.R.F.
8O 1S2 ,2S2 , 2P4 Oxygen, is divalent because
it has two unpaired electrons.

* Oxidation number: -
Def * It’s a number refers to the electric charges
(positive or negative) of elements in compound.
* Difference between [oxidation number and valence]
* Whose meaning is similar to valence. but the term oxidation number is preferred than valence because it helps us to explain the change in the electronic structure of atoms in compounds. G.R.F.
Example Valence Oxidation no. Example Valence Oxidation no.
Na+1 1 +1 Cl-1 1 -1
Mg+2 2 +2 O-2 2 -2
Calculation’s rules of oxidation numbers
1) The oxidation number of an atom in its elemental state equals zero.
Ex. [ O2 , O3 , N2 , S , H2 , O3 , S8 , P4 , Cl2 ]
2) Sum. oxidation numbers of any compound is zero H2 S O4
3) The oxidation number of Oxygen equals –2 except that
Oxygen diflouride Hydrogen peroxide Sodium peroxide
O F2 H2O2 Na2O2
O F2 H2 O2 Na2 O2
O = +2 O = -2/2 = -1 O = -2/2 = -1
4) The oxidation number of Hydrogen (+1) except [metal hydrides]
Ca H2 NaH
Ca H2 Na H
H = -2/2 = -1 H = -1
*On electrolysis of Sodium hydrides , Hydrogen gas evolves at anode
because oxidation number of Hydrogen in hydrides = -1 G.R.F
5) In the formula for an atomic group (radical) the sum of oxidation numbers equals the charge of the group. For example, in the radical.
(Cr2 O7 ) , the sum of all oxidation number is = -2
Calculate oxidation number in each of the following
1- Oxygen in {OF2 , KO2 , Na2O2 , Li2O , O3 , O2 }
2- Chlorine in { NaCl , NaClO4 , NaClO3 , NaClO2 , NaClO }
3- Nitrogen in { NO2 , HNO2 , NO , N2O , N2 , NH3 , ( NO3)-1,(NO2)-1
4- Sulphur in {Na2S2O3 , K2S , SO2 , NaHSO3 , H2SO4 , (SO4)-2
5- Manganese in {KMnO4 , MnO2 , (MnO4)-1 , MnCl2 }
6- Iron in {FeSO4 , Fe2(SO4)3 , }
7- Sulphur in { ferric sulphate , ferrus sulphate }
Fe2(SO4)3 FeSO4
*Oxidation number of some elements:-
Group 1A 2A 3A
O.N +1 +2 +3
Ex Li ,Na , K , Rb , Cs Be , Mg ,Ca , Ba Al
Oxidation :-
*It is the process of losing electrons leading to increasing the positive
charges or decreasing the negative charges
Reduction :-
*It is the process of gaining electrons leading to increasing the negative
charges or decreasing the positive charges
Oxidizing agent :-
Substance which takes electron , takes hydrogen or gives oxygen
Reducing agent :-
Substance which gives electron , takes oxygen or gives hydrogen


ليست هناك تعليقات:

إرسال تعليق