Chemistry Grade - 9 /Old Course (Science)

 

Chemistry           Grade -   9 (Science )

Unit                               Topics
8                                              Classification of Elements
9                                              Chemical Reaction
10                                            Metals                                                
11                                            Solubility                                           
12                                            Some Gases (H_2, O₂, N₂  )                                           
13                                            Carbon and its Compounds                                       
14                                            Water
15                                            Chemical Fertilizers used in Agriculture                                         
                         Specification Grid  -2074 
 Division of 22 marks in Knowledge(K) ,Understanding(Un), Application(AP), and Higher abilities(HA) types of questions 

Areas	S.N.	Units	Total no. of questions & their marks					Remarks
			K-20%	Un-35%	Ap-24%	HA-21%	Total
Chemistry	8 9 10 11 12 13 14 15	Classification  of  Elements Chemical Reactions Metals Solubility Some Gases (H2,O2,N2 ) Carbon and its Compounds Water Chemical fertilizers used in Agriculture	4x1= 4	4x2= 8	2x3= 6	1x4= 4	22 marks	Physics-56+ Chemistry-56+ Biolog-56+Geology &Astronomy-12 Periods=180 periods
	3		4	4	2	1	22 marks

Scholastic Areas  :-Grading on 9 points Scale

S.N.	Marks range	Grade	Attributes	Grade Points	Remarks
1 2 3 4 5 6 7 8 9	90 to 100 80 to below 90 70 to below 80 60 to below 70 50 to below 60 40 to below 50 40 to below 50 30 to below 40 0 to below 20	A+ A B+ B C+ C D+ D E	Outstanding Excellent Very good Good Satisfactory Acceptable Partially Acceptable Insufficient Very insufficient	4.0 3.6 3.2 2.8 2.4 2.0 1.6 1.2 0.8	The minimum qualifying grade in all subjects under scholastic Domain Is C

 

          Unit :- 8     Classification of elements

Chemistry : The branch of Science consisting the study of matter is called chemistry .

Matter :Any substance which occupies space and have mass is called mater .For example :air water, Hydrogen, stone etc.

Element:Element: The pure substance which can not be converted or broken down into two or more simpler substance by any physical or chemical process is called element .There are about 118 elements in the nature .Out up these 92 elements are found in nature or formed naturally are called natural elements .Remaining 26 elements are man made, are called artificial elements .

On the basis of chemical and physical properties elements are divided into 3 types :They are :i) Metal i.e. Iron ,gold , silver etc.

ii.) Non metal : Hydrogen ,oxygen ,carbon ,etc.

iii.)Metalloid: Arsenic, antimony etc.

They are generally found in 3 states i.e. Solid e.g. :Gold ,silver ,Liquid e.g.: Mercury ,bromine ,and Gas e.g.: Hydrogen ,Oxygen ,etc     

Atom : The smallest particles element is called atom .For example: Atoms of  H. O, N, Na, Al, C, etc.

Properties of atoms: i.) They takes part in chemical reaction  without division.

ii.)They are electrically neutral .

iii.)They can neither created  nor destroyed .

iv)  They can not be further divided .

iv)It is the smallest unit of an element .

v)Except hydrogen all atoms are made up of electron, proton, and neutron.

vi)Except atoms of inert gases ,all other atoms do not exist independently .

Molecules: A smallest particles of an element or compound which can exist freely in nature is called molecule .The molecule of an element is made up one or more atoms of the same type .For example : molecule of oxygen (O₂), molecules of Hydrogen(H₂) .But molecule of compound made up dissimilar atom .For example :molecule of water which consist of two atoms of hydrogen and one atoms of oxygen .They do not take part in chemical reaction .

Properties of molecules :

i)Molecules is smallest particles of an element or compound which can exist freely in nature .

ii) They are chemically decomposible .

iii)In molecule atoms are bonded together by chemical bond .

Sub –atomic particle :According to Lord Earnest Rutherford an is made of three smallest particles i.e. Proton ,neutron, and electron are called subatomic particles .

Proton: The positively  charged subatomic particles is called proton .They are located in the Nucleus of atom .The mass of proton is equal to the mass of hydrogen i.e. 1 a.m.u. (atomic mass of unit ). It is denoted by P⁺ .

Neutron :The charge less  or Neutral subatomic particles of is called Neutron .They are located in the nucleus of an atom .The mass of neutron is equal to proton i.e. 1 a.m.u. It is denoted by n⁰ .

Electron : The negatively charged subatomic particle is called neutron .They are revolving around nucleus in an elliptical orbit .The mass of electron is about 1/1837 times the mass of hydrogen  or 1/1837 a.m.u. .It is denoted by e^- .

Nucleus   and Nucleons: The small   positively charged central part of an atom is called Nucleus .All protons and neutrons are present in the nucleus .

The protons and Neutrons present in the nucleus of an atoms are collectively known as nucleus .

Atomic number :The number of protons or electrons in an electrically neutral atom of an element is called atomic number .For example :H =1, He =2 ,Li =3 etc

Atomic number = N. of protons or N. of electrons

Atomic weight :The sum of number of protons and number of electrons in an atoms of element is called atomic mass . For example :atomic mass of He =2+2 =4  ,carbon =6+6=12 ,Nitrogen =7+7=14

Atomic number and atomic weight :

Atomic N. or Proton or electron	Name of element	Symbol	N. of Neutrons	Atomic mass or weight
1	Hydrogen	H	0	1
2	Helium	He	2	4
3	Lithium	Li	4	7
4	Berelium	Be	5	9
5	Boron	B	6	11
6	Carbon	C	6	12
7	Nitrogen	N	7	14
8	Oxygen	O	8	16
9	Fluorine	F	10	19
10	Neon	Ne	10	20
11	Sodium	Na	12	23
12	Magnesium	Mg	12	24
13	Almunium	Al	14	27
14	Silicon	Si	14	28
15	Phosphorus	P	16	31
16	Sulphur	S	16	32
17	Chlorine	Cl	18	35
18	Argon	Ar	22	40
19	Potassium	K	20	39
20	Calcium	Ca	20	40

Compound :The substance which is formed by the combination of two or more elements by any chemical reaction in definite proportion by weight is called compound .

Properties of compound :

i)Compounds are formed by the combination of two or more elements in definite proportion by weight .

ii)They are formed by chemical reaction .

iii)Properties of compound are different from the properties of their constituents due to chemical reaction and chemical change .

iv)Compound are chemically pure substance .

v)Element of compound can be separated by chemical method.

Types of compound : They are two types :

1.)Electrovalent compound :-The compound  which is formed by transfer of  valence electrons between two atoms is called electrovalent compounds or ionic compounds .These compounds contains electrovalent bonds .They are formed generally from the combination of Metal and non metal .These compound can be electrolyzed .For example: Sodium chloride(NaCl ), Potassium chloride (KCl ) ,Magnesium oxide (MgO ) etc.

Properties :

i)Electrovalent or ionic compounds have high melting point .

ii)They are soluble in water .

iii)They do not have fixed geometrical shape .

iv)In fused or solution state  they conduct electricity .

2.)Covalent compound : The compound which is formed by sharing of valence cell of electrons between two elements is called covalent compound .These compound contains covalent bond .They are formed generally by the combination between non metals .These compound can not be electrolyzed. For example : Methane (CH₄ ), water (H₂O) ,Ammonia( NH₄) etc.

Properties:-

i)Covalent compound have less melting and boiling point as compared  to electrovalent compound .

ii)They are insoluble in water but soluble in organic compound .

iv) They have fixed geometrical shape .

v)They do not conduct electricity .

Chemical bond :A force of attraction that is established between the atoms in a molecules after the sharing or transfer of valence electrons is called bond .   They are three types :

 1)Electrovalent bond or  ionic bond

2)Covalent bond  or molecular bond

3)Co ordinate covalent bond

1)Electrovalent bond or ionic bond :The bond which is formed by the transfer of valence electrons between atoms is called electrovalent bond or ionic bond .For example : bond between  NaCl ,MgCl₂ ,K ₂O etc

2)Covalent bond :The bond which is formed by the mutual  sharing of equal valence electrons between same or different atoms  is called covalent bond or molecular bond .For example: Bond between CH₄ ,H₂O,NH₄ ,H₂ ,O₂ etc .       It is three types :

i)single covalent bond :In covalent bond if one electron is contributed by each atoms is called single covalent bond .It denoted by  -

ii)Double covalent bond :In covalent bond if two electrons are contributed by each atoms is called covalent bond .It is denoted by  ＝

iii) Triple covalent bond :in covalent bond if three electrons are contributed by each atom is called triple covalent bond .It is denoted by ≡

3)Co ordinate covalent bond :The bond in which an atom share its electrons with another  atom but second atom accept electrons but does not share or only one side sharing  is called co ordinate covalent bond .It is denoted by →

Ion :The electrically charge atom is called ion .They have eight electrons to their valence shell .In ions number of electrons and protons are not equal .They are two types :

i)Cat ion  or positive ion :When an atoms losses electrons, it become positively charged and carries positive charge .Such positive charge atom is called cat ion .For example : Ca^{+ +}  ,Mg⁺⁺,Na⁺, K⁺ etc

ii)Anion or Negative ion :When an atom gains electrons ,it become negatively charged and carries negative charge .Such negative charge atom is called an ion .For example :Cl^-, O^{- -}  ,Br ^– etc

Inert or Noble gas :The gas which have 2 electrons in K shell and 8 electrons in valence shell are called inert gas .They do not take part in chemical reaction and their valency is zero because valence shell of inert are  already full fill ,so they neither receive or donate electrons during chemical reaction .They are also two types :

i)Duplet inert gas :If an atoms has only K shell and two electrons are present in it is called duplet inert gas .For example: i)Helium (He)

ii)Octet inert gas :If an atoms has only 8 electrons to their valence are called octet inert gas .For example:  ii)Neon (Ne)  iii) Argon (Ar)  iv)Krypton(Kr)  v)Xenon (Xe) vii)Randon (Rd)

Valency :The combine capacity of element or radical to another element or radial to form compound is called  valency .

Or  the capacity of element to sharing or losing of valence electrons to their valence shell is called valency . It is reperesented by the numbers i.e. 1,2,3,4,5,6, For example valency of Oxygen is 2 ,hydrogen is 1 .

Valence shell :The outer most shell of an atom is called valence shell .

Valence electrons :The number of electrons present in valence shell is valence electrons .Valence shell of valence electrons help to determine valency of element ,reactivity, Group of element,Metal,Non metal,Metalloid, etc . For example :valence electrons of oxygen is 6 so gaining capacity 2  electrons and valency is 2 , valence electrons of Mg is 2 ,so losing capacity is 2 and valency is 2 .

Penultimate shell :The second outer most shell or the inner shell next to valence shell is called penultimate shell .

Duplet rule:The tendency of an atom to hold 2 electrons in their first outer most shell is called duplet rule.

Octet rule :The tendency of an atom to hold 8 electrons ti their outer most shell is called octet rule .

1.)What do you mean that the valency of Al is 3 ?

Ans. It means that the combing capacity of Al is 3 i.e.It can donate electrons to other during compound  formation .

Radical :A radical is an atom or group of atoms different element having positive or negative charge and act as single unit during chemical reaction is called radical .They are two types :

i)Electropositive radical or Basic radical :The radical which have the capacity of losing electrons and carry positive charge are called electropositive radical .For example Mg⁺⁺ ,(NH₄)

Radical                 Valency of elements                      Valency of radicals

Ammonium  (NH₄)   = + 5-4                          =      +1

 ii)Electronegative radical or acidic radical :The radical which have the capacity of gaining electrons and carry negative charge are called electronegative radical .For example :O^{-- --}  (SO₄)

Radical                 Valency of elements                      Valency of radicals

Carbonate (CO₃)  = +4-6                                = -2

Bicarbonate (HCO₃)  = +1+4 -6                   = -1

Sulphate (SO₄)     = +6-8                                =2

Bisulphate (HSO₄)  =+1+6 -8                       =  -1

Nitrate (NO₃)  = +5-6                                                      = -1

Hydroxide (OH) = -2+1                                                  = -1

 

Valency chart :

S.N.	Name of element s	Symbol		Valency
		Electro positive	Electro Negative
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21	Hydrogen  or hydride Potassium Sodium Silver Gold-I(Aurous) Copper –I (Coprous) Mercury –I(Mercurous) Ammonium Bicarbonate Bisulphate Hydroxide Nitrate Nitrite Chlorate Chlorite Chlorine or chloride Bromine or bromide Fluorine  or fluoride Iodine or iodide Cyanide Bisulphite	H K Na Ag Au Cu Hg (NH4)	(HCO3) (HSO4) (OH) (NO3) (NO2) (ClO3) (ClO2) Cl Br Fl I CN (HSO3)	1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43	Barium Calcium Magnesium Nickel Zinc Coppper –II(Cupric) Iron –II(Ferrous) Mercury –II(Mercuric) Lead –II (Plumbous) Tin-II(Stannous) Magnanese Iron –II(Ferrous) Oxygen or oxide  Sulpher or Sulphide Peroxide Carbonate Sulphate Sulphite Chromate Dichromate Silicate Stanate 11	Ba Ca Mg Ni Zn Cu Fe Hg Pb Sn Mn Fe	O S O2 (CO3) (SO4) (SO3) (CrO3) (Cr2O7) (SiO3) (SnO3)	2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
44 45 46 47 48 49 50	Aluminium Nitrogen or Nitride Phosphrous  or phosphide Chromium Iron-III (Ferric) Gold –III (Auric) Phosphate	Al     Cr Fe Au	N P       (PO4)	3 3 3 3 3 3 3
51 52 53 54 55	Lead –IV (Plumbic) Tin-IV(Stanic) Sulpher or sulphide Silicon Carbon or carbide	Pb Sn S Si C		4 4 4 4 4
56 56	Nitrogen or nitride Phosphrous	N P		5 5
57	Sulpher	S		6

 Molecular formula :The symbolic representation of molecules of substance which show actual number of atoms present in the molecules is called molecular formula or chemical formula .For example :i) Magnesium chloride =MgCl₂, Sodium sulphate =Na₂(SO₄ ) etc.

Ways of writing molecular formula : This method is called criss –cross method.

i)Write the symbols side by side but electropositive is written first and then electronegative .

ii)Write the valency of each atom at top of its symbol .

iii)Divide the valency numbers by highest common factor then inter change the valency of symbol .

iv)Write the  inter changed valency number to the lower of the symbol .

Molecular formula of some compounds :

Name of compounds           Molecular formula

Water =                               H₂O

Carbondixide    =            CO₂

Carbonmonoxide =         CO

Ammonia              =        NH₃

Castic soda                         =    Na(OH)

Castic Potash                     = K(OH)

Methene                             = CH₄

Calcium carbonate  or limestone              =Ca(CO₃)

Lime water                         = Ca(OH)₂

Lime                                      ₌ CaO

Hydrochloric acid            =HCl

Sulphuric acid                   H₂(SO₄)

Nitric acid                           =H(NO₃)

Carbonic acid                     =H₂(CO₃)

Acetic acid                          =CH₃COOH

Carbon sulphide              =CS₂

Nitric oxide                        =NO

Hydrogen peroxide        =H₂O₂

Iron oxide (rust)                               =Fe₂O₃

Manganese dioxide       =MnO₂

Silica(Silicon oxide )       =SiO₂

Urea                                      =NH₂-CO-NH₂

Diatomic elements         =H_2,O_2,N_2,Cl_2,Br_2,I_2,F_2,

2n² rule :The rule that gives the maximum number of electrons present in the shell is called 2n²   rule .For example :

i)K- shell = 2n²  

               = 2 x1²  =2 electrons.

ii)L- shell  = 2n²

           =2x 2²    = 8 electrons

iii)  M  -Shell =  2n²

                       = 2x 3²  =18 electrons

Name of shell                                  Number of shell

K  =                                                         1

L  =                                                         2

M  =                                                       3

N=                                                          4

O  =                                                        5

P  =                                                         6

Q   =                                                       7

Differences between shell and sub shell .

Shell	Sub shell
i)A circular path on which electrons revolute around the nucleus is called shell . ii) It is denoted by K,L,M,N,O,P,Q	i)A part of shell is known as sub shell .ii) It is denoted by s,p,d,f

Difference between orbit and orbital

Orbit	Orbital
i)A circular path on which electrons revolute around the nucleus is called shell . ii)All orbit are circular and disc like .	i)The region around  nucleus in which probability of finding the electrons  maximum is called orbital. ii)Different orbital have shape and half filled or full filled orbital more stable than other .

Electronic configuration :The systematic  distribution of electrons according of their shell and sub shell is called electronic configuration .

Variable valency :The element which has more than one valency is known as element of variable valency . It is generally  denoted by ous and ic form in which ous show lower valency and ic show higher but ic is stable than that of ous form . .For example ferrous have 2 and ferric have 3 valency . 

 Note :

Metal =Valence electrons :1,2,3 For example :Na, K

Non Metal= Valence electros:5,6,7  for example :Cl, O, Br

Metalloid = valence electrons :4 ,For example :Si, Ge, As, Te

Inert gas : valence electrons :8  For example :Ne ,Ar, Kr ,xe, Ra

N. of group : Total valence electrons i.e.  IA ,IIA ,IIIA group

N. of  period =: N. of shell

Valency :valence electron 1=1 ,2 =2,3=3,4=4,5=3,6=2,7=1,and 8=0 valency

1.)Atomic number of Na is 11 and oxygen is 8 respectively .Answer the following questions on the basis of that .

i)Write the electronic of Na, and  O .

ii)Write name the group of Na and O ?

iii) Write name the period of Na,and O ?

iv)Write valency of Na and O?

v)Which one is metal and Non metal ?

i)Na =11

1s² ,2s² ,2p^6, 3s¹

 K          K        L

ii) O=9

1s², 2s², 2p⁴

K           L

ii)Na =IA group

   O=  VIA group

iii)Na =3^rd period

     O =2^nd period

iv) Na =1 valency

     O =   2 valency

v)Na =metal

 O = Non metal

          Unit -9        Chemical reaction

Chemical reaction :-The exchange ,combustion or decomposition that occurs in the molecules of substances during a chemical change is called chemical reaction .

Chemical equation : The symbolic representation of the chemical reaction by writing the symbol and formula is called chemical equation .It is divided into two parts :

i)Reactant :The substance which takes part in chemical are called reactants .They are always  written in the left side of the chemical equation .

ii)Product :The substance obtained from a chemical reaction are called product .They are always written in the right side of the chemical equation .

i)Hydrogen +Oxygen                  Water

2H₂    +O_2→                 2 H₂O

ii)Sodium +Oxygen                  Sodium oxide

Na +O_{2      →}                               Na₂O

Word equation :The chemical equation in which the names of substance and products are expressed in the form of word is called word equation . For example :

 i)  Hydrogen + Oxygen    _→                                     water

ii) Magnessium + Oxygen   _→                                  Magnesium oxide

iii)Calcium carbonate                    _→                         Calcium oxide +Carbon dioxide

Types of chemical reactions :There are 4 types chemical reaction:

1)Combination reaction :The chemical reaction in which two or more elements or compounds combine to form a single compound is called combination reaction .For example :

1)Sodium + Oxygen                 Sodium oxide

4Na     `+ O_{2        →}                      2Na₂O

2)Magnesium + Oxygen       _→                            Magnesium oxide

2Mg     +          O_{2       →}                           2MgO

3)Hydrogen + Chlorine      _→                   Hydrogen chloride

H₂   +  Cl_{2                                →                                    2} HCl

4)Zinc +Chloride      _→                 Zinc Chloride

Zn  + Cl_2   →                     ZnCl₂

5)Nitrogen + Hydrogen       _→                          Ammonia

N₂      +     2H_{3                     →}       2NH₃

6)Iron + Oxygen        _→                Iron oxide

Fe   +  O_{2                              →}               Fe₂O₃

7)Magnesium +Nitrogen               _→                   Magnesium Nitride

3Mg +  N_{2                        →}          Mg₃N₂

8)Carbon dioxide +Water        _→                         Carbonic acid

  CO₂        +H₂O                 _→              H₂CO₃

9)Aluminum + Oxygen         _→                 Aluminum oxide

Al  +O_{2                            →}           Al₂O₃

10)Aluminum + Chlorine                       _→      Aluminum Chloride

2Al    + 3Cl_{2              →}                           2AlCl₃

11)Ammonia +Hydrochloric acid    _→      Ammonium chloride

NH₃       + HCl        _→                    (NH₄)Cl

12)Nitrogen +  Oxygen          _→               Nitric oxide

N₂     + O_{2              →}          2NO

13)Calcium oxide + Water    _→                Calcium hydroxide

CaO     +  H₂O           _→             Ca(OH)₂

14)Sodium oxide        +Water       _→                  Sodium hydroxide

Na₂O   +H₂O       _→                       2Na(OH)

15)Magnesium oxide +Water                _→           Magnesium hydroxide

16)Ammonium oxide +Water  _→           Ammonium hydroxide

(NH₄)₂O    + H₂O       _→                2(NH₄)(OH)

2.)Decomposition  reaction :-The chemical reaction in which a compound split or decompose into two or more elements or compound is called decomposition reaction .For example:

1)Water        _→                             Hydrogen   + Oxygen

2H₂O             _→                 2H₂     + O₂ 

2)Potassium chlorate    _→       Potassium chloride + Oxygen

2K(ClO₃)    _→                    2KCl     + 3O₂

3)Calcium carbonate     _→     Calcium oxide +Carbon dioxide

Ca(CO₃)            _→                         CaO                 + CO₂

4)Magnesium oxide       _→           Magnesium +Oxygen

2Mg O       _→                    Mg + O₂

5)Hydrogen peroxide   _→                Water + Oxygen

2H₂O_{2                                  →}                     2H₂O +O₂

6)Calcium bicarbonate          _→               Calcium carbonate +Carbon dioxide +Water

Ca(HCO₃)_{2           →}          Ca(CO₃) +CO₂    +H₂O

7)Magnesium bicarbonate     _→              Magnesium carbonate +Carbon dioxide +Water

Mg(HCO₃)_{2         →}                       Mg(CO₃) +CO₂  +H₂O

8)Silver Bromide     _→                  Silver  + Bromine

2Ag Br       _→                                2Ag  +Br₂

 9)Potassium Permanganate  _→      Potassium manganate  +Manganese dioxide +Oxygen

2KMnO_{4     →}                   K₂MnO₄ +MnO₂  +O₂

10)Ammonium carbonate            _→      Ammonia +Carbon dioxide +Water

(NH₄)₂(CO₃)  _→                2NH₃    +CO₂    +H₂O

 3.Displacement reaction :The chemical reaction in which an element or radical of a compound is displaced by another element or radical of compound is called displacement reaction .For example :

1)Zinc +Sulphuric acid  _→                 Zinc sulphate +Hydrogen

Zn +  H₂(SO₄)          _→          Zn(SO₄ )  +   H₂

2)Zinc  + Hydrochloric acid            _→     Zinc chloride + Hydrogen

  Zn       +   2HCl              _→          ZnCl₂   +  H₂

3)Potassium + Nitric acid            _→ Potassium Nitrate +  Hydrogen

   2 K  + 2H(NO₃)      _→                 2K(NO₃)    +  H₂

3)Iron + Copper Sulphate           _→    Iron Sulphate +Copper

2 Fe +3 Cu(SO₄)     _→             Fe₂(SO₄)₃   + 3Cu

4)Aluminum  + Hydrochloric acid  _→           Aluminum chloride +Hydrogen

2 Al      +6 HCl                  _→                       2AlCl₃  + 3 H₂

5)Magnesium + Copper Sulphate _→          Magnesium Sulphate + Copper

 Mg + CuSO_{4                     →}                    Mg(SO₄)  + Cu

6)Sodium + Water     _→                Sodium hydroxide + Hydrogen

2 Na +2H₂O          _→                     2Na(OH) +H₂

7)Magnesium bicarbonate        _→                        Magnesium carbonate +Carbon dioxide +Water

Mg(HCO₃)_{2                     →}                        Mg(CO₃) +CO₂  +H₂O

8)Silver Bromide       _→                             Silver  + Bromine

2Ag Br                             _→                       2Ag  +Br₂

 

9)Potassium Permanganate    _→                Potassium manganate  +Manganese dioxide +Oxygen

2KMnO_{4           →}                          K₂MnO₄ +MnO₂  +O₂

10)Ammonium carbonate        Ammonia +Carbon dioxide +Water

(NH₄)₂(CO₃)         _→                       2NH₃    +CO₂    +H₂O

 3.Displacement reaction :The chemical reaction in which an element or radical of a compound is displaced by another element or radical of compound is called displacement reaction .For example :

1)Zinc +Sulphuric acid       _→                        Zinc sulphate +Hydrogen

Zn +  H₂(SO₄)                _→                 Zn(SO₄ )  +   H₂

2)Zinc  + Hydrochloric acid                 _→             Zinc chloride + Hydrogen

  Zn       +   2HCl           _→                          ZnCl₂   +  H₂

3)Potassium + Nitric acid           _→              Potassium Nitrate +  Hydrogen

   2 K  + 2H(NO₃)                     2K(NO₃)    +  H₂

3)Iron + Copper Sulphate             _→               Iron Sulphate +Copper

2 Fe +3 Cu(SO₄)      _→                         Fe₂(SO₄)₃   + 3Cu

4)Aluminum  + Hydrochloric acid             _→             Aluminum chloride +Hydrogen

2 Al      +6 HCl           _→                                           2AlCl₃  + 3 H₂

5)Magnesium + Copper Sulphate    _→                     Magnesium Sulphate + Copper

 Mg + CuSO_{4                          →}                            Mg(SO₄)  + Cu

6)Sodium + Water       _→                           Sodium hydroxide + Hydrogen

2 Na +2H₂O          _→                                  2Na(OH) +H₂

 

7)Magnesium+ Water     _→                      Magnesium hydroxide +Hydrogen

 Mg + H₂O      _→                            Mg(OH)₂          +H₂

8)Zinc +Silver Nitrate  _→                          Zinc Nitrate +Silver

   Zn + 2Ag(NO₃)        _→                            Zn(NO₃)₂  +2Ag

9)Calcium +Water       _→                          Calcium hydroxide +Hydrogen

  Ca +2H₂O      _→                           Ca(OH)₂ +H₂

10)Aluminum +Sulphuric acid       _→                                Aluminum Sulphate+ Hydrogen

2Al+3 H₂(SO₄)      _→                                  Al₂(SO₄)₃ +6H₂

11)Copper +Silver Nitrate    _→                     Copper Nitrate +Silver

   Cu +  2Ag(NO₃)           _→                        Cu(NO₃)₂ +2 Ag

12)Ammonia +Chlorine           _→             Ammonium Chloride +Nitrogen

8NH₃ +3Cl_{2            →}             6 ( NH₄)Cl     +N₂    

13)Calcium Chloride +Silver Nitrate      _→                    Calcium Nitrate +Silver Chloride

CaCl₂ + 2Ag(NO₃)        _→                           Ca(NO₃)₂+2AgCl

14)Calcium Carbonate +Hydrochloric acid      _→                         Calcium Chloride +Carbon dioxide +water

 Ca(CO₃) +2HCl     _→                     CaCl₂ +CO₂ +H₂O

15)Sodium Chloride +Silver Nitrate         _→                      Sodium Nitrate+ Silver Chloride

 NaCl +Ag(NO₃)    _→                     Na(NO₃)+ AgCl

16)Calcium Carbonate +Sulphuric acid            _→             Calcium Sulphate +Carbon dioxide +Water

Ca(CO₃)+H₂(SO₄)       _→                             Ca(SO₄)+CO₂ +H₂O

17)Magnesium Sulphate +Sodium Carbonate     _→                                            

Magnesium Carbonate +Sodium Sulphate

Mg(SO₄)+Na₂(CO₃)        _→                        Ma(CO₃)+Na₂(SO₄)

4)Acid –Base reaction :The Chemical reaction in which an acid react with a base to form salt and water is called acid- base reaction .In acid base reaction both acid and base loss their properties during chemical reaction and form neutral substance salt and water ,so it is also called Neutralization reaction .

Some acids :

i)Hydrochloric acid=HCl

ii)Sulphuric acid =H₂(SO₄)

iii)Nitric acid =H(NO₃)

iv)Carbonic acid =H₂(CO₃)

Some bases :

i)Metal oxide ePdf = Mgo,Na₂O,K₂O,CaO etc.

ii)Metal hydroxide ePdf = Na(OH),K(OH),Ca(OH)₂ etc.

1)Sodium Hydroxide +Hydrochloric acid    _→                   Sodium Chloride + Water

2Na(OH)+2HCl        _→                               2NaCl +H₂O

2)Sodium Oxide +Hydrochloric acid    _→                       Sodium Chloride +Water

Na₂O   +2HCl          _→                   2NaCl +H₂O

3)Calcium Oxide +Sulphuric acid  _→                      Calcium Sulphate +Water

CaO +H₂(SO₄)   _→                           Ca(SO₄)+H₂O

4)Magnesium Oxide +Hydrochloric acid   _→                        Magnesium Chloride +Water

MgO+2HCl         _→                        MgCl₂ +H₂O

5)Potassium Hydroxide + Hydrochloric acid       _→                      Potassium Chloride +Water

2K(OH)+2 HCl                 _→                       2KCl +H₂O

6)Sodium Hydroxide +Sulphuric acid     _→                        Sodium Sulphate +Water

2Na(OH) +H₂(SO₄)  _→                         Na₂(SO₄)+2H₂O

7)Ammonium Hydroxide +Sulphuric acid      _→                            Ammonium Sulphate + Water

2(NH₄)(OH) +H₂(SO₄)      _→                          (NH₄)₂(SO₄)+H₂O

8)Magnesium Hydroxide + Nitric acid         _→                             Magnesium Nitrate + Water

Mg(OH)₂ +2H(NO₃)       _→                         Mg(NO₃)₂   +H₂O

Types of reaction according to heat :There are two types of reaction according to heat :

1.)Exothermic reaction : The reaction in which heat is released to the surrounding  is called exothermic reaction. For example :

i )C + O _{2                      →}                                 CO₂  +Heat

ii) C₆H₁₂O₆ +6O_{2            →}           6CO₂ + 6H₂O Energy +Heat

2.)Endothermic reaction :The reaction in which heat is absorbed from the surrounding is called endothermic reaction .For example :

i)Ca(CO₃)  + Heat                   _→               CaO +CO₂

ii)2K(ClO₃)            _→                   2KCl + 3O₂

Some rules of what happens :

Reactants                                                       Product

i)Single 2 elements   =    Combination of element .i.e.

Na + Cl_{2          →}                                     NaCl

Mg + O_{2                  →}                                                               MgO

ii)Metal  +Water =      Metal Hydroxide i.e.

Na+ H₂O       _→                           Na(OH)

Ca  +H₂O      _→                           Ca(OH)₂

iii)Metal +Water  = Metal Hydroxide +Hydrogen i.e.

 Mg + 2H₂O       _→                    Mg(OH)₂ +H₂

Na+2 H₂O    _→                      Na(OH)₂  +H₂

iv)Acid+ Base  = Salt + Water

  HCl +Na(OH)     _→                      NaCl +H₂O

H₂(SO₄) +Na₂ O     _→                    Na₂(SO₄) +H₂O

v)Carbonate + acid =  Carbon dioxide + Water  i.e.

 Ca(CO₃)+2HCl     = CaCl₂  + CO₂  +H₂O

Balanced chemical equation : The chemical equation written by balancing the N. of atoms of element on both sides of reactants and products is called balanced chemical equation .For example :

2H₂ + O_{2      →}                            2H₂O

Advantages  or information can be obtained from of balanced chemical reaction : Following information can be obtained from balanced chemical equation :

i)The types of chemical equation

ii)Names of reactants and produced

iii)Molecular formula  or symbols of reactants and products

iv)N. of atoms and molecules of reactants and products .

Limitation of a balanced chemical equation :The information which can not show a balanced chemical equation are called limitation of balanced chemical equation .They are as following :

i)Rate of chemical equation .

ii)Concentration of reactants .

iii)Duration of chemical reaction .

iv)Conditions necessary for chemical reaction .

Factors affecting chemical reaction or chemical change :

1)Heat :When reactants are heated more kinetic energy provides to the reactants molecules ,that increase the rate of reaction by colliding with one another molecules .i.e.

Calcium Carbonate        _→                     Calcium oxide +Carbon dioxide                    

   Ca(CO₃)         _→                         CaO + CO₂

2)Light :Light makes the reactants molecules more reactive and help to increase the rate of reaction .

Silver Bromide    _→            ^Light                 Silver +Bromide

2AgBr     _→               ^Light                2Ag + Br₂

3)Electricity :The electrical energy help the ions to move to wards  opposite. charged electrodes that brings out a chemical change and increase the rate of reaction .

Water      _→                    Hydrogen +Oxygen

2H₂O    _→               ^Electrolysis                    2H₂ +   O₂

4)Direct Contact :Some  active substance react on coming in direct contact with other .i.e.

Sodium + Chlorine   _→               ^{Direct contact}                  Sodium Chloride

2Na + Cl_2  →             ^{Direct contact}     2 NaCl

5)Pressure :Some chemical reaction takes place by the application of pressure .i.e.

Nitrogen + Hydrogen     ^{200 atm-900 atm}                Ammonia

N₂  +3H_2  →             ^{200 atm-900 atm}                 2 NH₃

6.)Surface area :The rate of chemical reaction is directly proportional to the surface area of the reacting molecules ,because there is more chances to contact and collision between reacting particles .For example :During preparation of hydrogen gas if the granulated zinc has more area the chemical reaction proceeds in faster rate .

7.)Solution :The chemical reaction between some compounds only occurs when they are in the state of solution .For example :Silver nitrate and Sodium chloride only react when they are mixed in the solution state

Ag(NO₃) (aq.) + NaCl (aq.)       _→                       Na(NO₃) +AgCl

8.)Concentration : The rate of chemical reaction increase with the increase in the concentration of the reactants because concentration of reactants increase the number of molecules per unit volume that increases more collision between reactants molecules .

9)Catalyst :A chemical substance which changes the speed of rate of chemical reaction with out changing itself is called the catalyst . There are 2 types of catalyst :

i)Positive catalyst :A catalyst which increase the rate of chemical reaction is called positive catalyst .i.e. Manganese dioxide acts as positive catalyst in a decomposition reaction of potassium chlorate .

Potassium Chlorate     _→             MnO₂            Potassium Chloride + Oxygen 

2K(ClO₃)    _→            MnO₂        2KCl +3O₂

ii)Negative Catalyst :A catalyst which decrease the rate of chemical reaction is called negative catalyst .i.e. Glycerin acts as negative catalyst in decomposition of hydrogen peroxide .

2H₂O_2  →          Glycerin      2H₂O  + O₂

Gram atomic weight : The atomic weight of an element expressed in gram is known as gram atomic weight of that element .For example :The gram atomic weight of oxygen is 16 gm ,because the atomic weight of oxygen is 16 .

1.)Find the atomic weight of Na, K ,and Ca atoms .

            Na =11+12

                 =23 gm

           K = 19+20

               =  39 gm

          Ca =20+20

               = 40 gm

Gram molecular weight :The molecular weight of the substance is expressed in gm is known as gram molecular weight of that substance .For example :The gram molecular weight of water is (H₂O) is 18 gm because molecular wt of water is 18 .

1.)Find the molecular weight of given compounds .

i)H₂O

= 1x2+16

18 gm

ii)CaO

= 40+16

=56 gm

iii)Ca(CO₃)

= 40+12+16x3

=40+12+48

=100gm

                Unit :- 10               Metal

Metal :-The elements which have  a tendency to loss electrons and form cat ion are called metal .For example :Mg, Na, Ca, Al etc.

Properties of metals:

Physical properties:

i)Most of metals are solid at ordinary temperature ,except mercury ,it is found in liquid state .

ii)Most of metals are generally hard ,except Na, K, Li, they are soft .

iii)Metal posses metallic luster (shining)

iv)Metals have generally high density ,except Na, K ,Li.

v)Metal posses ductile property (i.e. can be change into wires)except Na, K, Li.

vi)Metals are generally good conductors of heat and electricity .

vii)The boiling and melting point of metals are high ,except Na, K, Li.

viii)Metals atoms generally contains 1,2,3,electrons to their valence shell .

ix)Metals are generally electropositive in nature because loss their valence electrons.

x)Metals possess malleability (i.e. can be beaten in thin plate)

Chemical properties :

Non metal :The element which have a tendency to loss electrons and form anions are called non metal .For example :H_{2 ,}O_{2 ,}Cl_2, Br_2, N₂ etc.

Properties :

i)Non metals are generally found in all three states i.e. solid For example: Carbon ,liquid For example: Bromine ,gas For example :Hydrogen ,Oxygen, Nitrogen etc.

ii)Non metals are generally soft and light ,except carbon in the form of diamond and graphite .

iii)Non metals have generally very low melting points ,except carbon.

iv)Non metals have generally very low density ,except iodine.

v)Non metals are generally not ductile ,except carbon.

vi)Non metal are not malleable .

vii)Non metal are generally brittle (i.e. break  when force is applied )

viii)Non metals are non conductor of heat and electricity .

ix)Non metals generally contains 4 or more than 4 electrons to their valence shell.

Metalloid :The elements which show properties of both metals and non metal are called metalloid .For example :Boron (B),Silicon(Si),Germanium (Ge), Arsenic (As) ,Antimony (Sb),and Tellurium (Te) etc.

Properties of metalloid :

i)They are poor conductor of heat and electricity .

ii)They posses metallic luster .

iii)They form alloys .

iv) They are neither malleable nor ductile .

v)They are generally solid in state .

vi)They are brittle in nature .

v)They can conduct heat and electricity better than non

metal less than metal .

Uses of metalloids :

i)Tellurium is used in manufacture of electric resistors, rubber, ceramics ,glass .

ii)Antimony is used in several alloys i.e. glass .

iii)Silicon is used in the manufacture of electronic devices .

Alloy: A homogenous mixture of two or more than metal or non metal are called alloys .For example :Brass .

Properties of alloys :

i)They are generally harder than their components .

ii)They are good conductors of heat and electricity .

iii)They are malleable and ductile .

iv)Alloys increase the strength of metal .

Roles of some metals in human body :

1.)Roles of Zinc in human body :It is found in small amount inside the body of organism .i.e. in adult about 2-3 gm Zn is found in cell , tissue, bone, retina, and abdomen.

i)It support the body to make healthy .

ii)It help to synthesis D.N.A. (De oxy ribonucleic acid)

iii)It is necessary for wound healing .

iv)It support for healthy growth and development of the body during adolescence, childhood and in pregnancy to develop embryo.

v)It act as a cofactor for enzyme

vi)It help for physical functions in the bone ,kidney and

brain.

2.)Roles of Sodium and Potassium in human body :Sodium and potassium ions are found out side as well inside of the cell .

i)The ions of Na and K act as power generator inside the cell of human body .

ii)They are responsible to transport and maintain electrical impulses in the body .

iii)They control P^H values of solution present inside the cell.

 

Effects due to irregularity of Na and K :

i) It is causes of migrain.

ii) It is causes of Blood pressure

iii) It is causes of paralysis .

Harmful effect of mercury :

i)It is causes of depression .

ii)It is causes of memory loss .

iii)It is causes of heat attack .

iv)It is causes of skin discolouration

Harmful effect of Lead :

i)It is causes of anaemia.

ii)It is causes of hyper tension.

iii)It is causes of headache and stomach pain.

iv)It is also may lead to coma and death .

Uses of metals in our daily life : 

i)Metals are widely used for making household utensil, cooking vessels .

ii)The foils of metals i.e. aluminum are used for packing foods stuff, soaps, cigarettes, photographic films etc.

iii)Metals i.e. aluminum ,copper etc. are used for making electric cable,

iv)The i.e. aluminum used for making aero plane ,ship buses trucks etc.

v)They are used for making machine tools ,automobile parts ornaments etc.,  

                                                            The End 

Unit :-10                Solubility

Mixture :The substance in which two or more than two substances  are mixes with each other any proportion by weight is called mixture .For example :Air ,milk, water ,sand ,sugar etc.

Types of mixture on the basis of nature of components of mixture :They are two type:

a)Homogenous mixture :The mixture in which components of mixture are equally distributed and component particles of mixture can not be seen init by naked eye is called homogenous mixture .For example :Salt water solution, alcohol water solution ,soda water etc.

b) Heterogeneous mixture : The mixture in which components of mixture are equally  not distributed and component particles of mixture can be seen init by naked eye is called heterogeneous mixture .For example :Muddy water ,Oily water ,Milk ,Blood etc.

b)On he basis of size of the components particles of mixture : They are 3 types :

i)Solution :A homogenous mixture of solute and solvent is called solution .For example :Solution of salt and water ,solution of sugar and water ,solution of alcohol and water etc.

or The homogenous mixture in which the size or diameter of solution  particles component is smaller than 10^-7 cm is called solution .

Solution =Solute +Solvent

Solute :  The substance which get dissolved in solvent is called solute .For example :Salt ,Sugar etc . Generally the amount of solute is less than that of solvent in the solution.

Solvent: The substance which help to dissolve the  solute is called solvent . For example :Water , alcohol ,petrol etc. Generally the amount of solvent is more than that of solute in solution .

ii)Colloids: The homogenous mixture in which the size or the diameter of solution particles components is between 10^-7 cm to 10^-5 cm is called colloids .For example : Blood ,Gum ,Milk etc.

iii)Suspension :The heterogeneous mixture of solid in liquid or solid in gas having size or diameter of solution particles of components is larger than 10^-5 cm is called suspension .For example :Mixture of sand and water , muddy water ,smoke in air etc.

Types of solution :

i)On the basis of temperature :They are 3 types :

i)Unsaturated solution :A solution in which  more solute can be dissolved in a particular temperature is called unsaturated solution . It become saturated solution with decrease in temperature or cooling  .

ii)Saturated solution : A solution in which  more solute can not  be dissolved in a particular temperature is called unsaturated solution . It become unsaturated solution with increase in temperature or heating.

iii)Super saturated solution :A solution in which more solute is dissolved by increasing the temperature of saturated solution is called super saturated solution .

Characteristics of super saturated solution :

i)When super saturated solution is stirred .It is changed into saturated solution .

ii)When we add a small amount piece of crystal of solute .It is changed into saturated solution .

iii)When temperature of super saturated solution is increased .It is changed into saturated solution .

b) On the basis of amount of solute :They are 2 types :

i)Dilute solution (dil) :A solution which contain small amount of solute in the compare of that solvent is called dilute solution .

ii)Concentration solution (Conc.) :A solution which contain large amount of solute in compare of that solvent is called concentration solution .

Solubility :-The  amount of solute that can dissolve in a 100 gm of solvent at a certain temperature to make saturated solution is its solubility.It have no unit .

 

Solubility =Wt of solute /Wt. of solvent   x100

Solubility curve :- A curve drawn in a graph to show a relationship between the temperature and the solubility of any substance at different temperature is called solubility curve .

Advantages from the study of solubility curves :-The following information can be obtained from study of solubility curve :

i)It help to compare the solubility of many substances at the same temperature .

ii)The solubility of solute at any temperature can be found out .

iii)The change in solubility on change in temperature can be observed .

iv) Solubility  of substances at different temperature an be found .

Uses of solution in our daily life :

i)Plants obtain their nutrients from the soil in the from of solution .

ii)Aquatic plants and animals found in water inhale oxygen dissolved in water as solution .

iii)Food taken by us is digested and absorbed in the form of solution .

iv)Most of drugs ,paints, etc. are in the form of a solution .

Numerical problems

1)2.5 gm of a solute are dissolved in 25 gm of water to from a saturated solution at 25⁰C .Find out the solubility of the solute at this temperature .

Given ,

Wt of solute =2.5 gm

Wt. of solvent =25 gm.

Solubility =?

We know that

Solubility = Wt of solute /Wt. of solvent   x100

          = 2.5 /25   x100

           =10

The solubility of solute of 25⁰C     is 10 .

2.)The solubility of sugar at 20⁰C is 204 .Calculate the amount of sugar that should be dissolved in 20 gm of water at 20⁰C to make a saturated solution .

Given,

Solubility of sugar=204

Wt of solvent  =20 gm

Wt. of solute =?

We  know that

Solubility = Wt of solute /Wt. of solvent  x100

Or 204 = Solute /20 x 100

Wt. of solute =40.8  

Wt . of solute =40.8 gm .

3)50 gm of a saturated solution of potassium nitrate in water at 30⁰C on evaporation leaves 15.8 gm of the solute .Calculate the solubility of potassium nitrate at that temperature .

Given ,

Wt of solution =50 gm

Wt. of solute = 15.8 gm

Wt of solvent =Wt of solution –Wt of solute

                          = 50- 15.8  =34.2 gm

Solubility = ?

We know that

Solubility =  Wt of solute /Wt. of solvent x 100

                =15.8 /34.2  x100

                 =46.2

Solubility at 30⁰C = 46.2

4.)How much common salt will be precipitated out if 160 gm of saturated solution of common salt at 30⁰C is cooled to 20⁰C (The solubility of common salt id 37 at 30⁰C and 35 at 20⁰C )

Given

At 30⁰C

Solubility =37

Wt. of solution=160 gm

Suppose wt. of solute = x

؞Wt. of solvent =160 – x

Now ,we know that

Solubility  = Wt of solute /Wt. of solvent  x 100

Or 37  = x/160-x  . 100

Or 100x  =37x160 -37

Or 100x +37x  = 37 x160

Or 137x  =37 x160

Or x  =37 x 160   /137

x=43.21 gm

wt. of solute at 30⁰C = 43.21 gm.

Wt. of solvent =160 – x

                          = 160 - 43.21

                          =116.79 gm.

Again  At 20⁰C

Given,

Solubility = 35

Solvent =116.79 gm

Wt. of solute = ?

We know that

Solubility =  Wt of solute /Wt. of solvent  x 100x100

Or 35 =Wt. of solute  /116.79  x 100

Or  wt. of solute =35 x  116.79 / 100

Or wt. of solute = 40.87 gm.

The amount of salt thrown out when solution is cooled from 37⁰C to 20⁰C is 43.21 -  40.87 = 2.34 gm.

 

Unit :- 11          Some Gases (H₂,O₂,N₂ )

A:- Hydrogen gas (H₂)

1)Introduction: The symbol of hydrogen gas is H, atomic N. 1, atomic mass 1a.m.u. ,molecular formula H₂, and valency is 1 .It was discovered by Henry Cavendish .It is generally found in volcanic eruption ,petroleum and organic substances i.e. hydrocarbon

                                                      Fig. Molecular structure of H₂ gas

2.)General preparation of H₂ gas .

i)By electrolysis of water :Hydrogen gas can be prepared from decomposition of water by electrolysis .

3.)Method of lab. preparation of H₂ gas :

i.)Apparatus required :Wolf bottle ,Thistle funnel ,delivery tube, gas jar, beehive self, heating apparatus.

ii)Chemicals required: zinc pieces, Sulphuric acid

iii)Principle:- H₂ gas can be  prepared by heating zinc pieces with dil. Sulphuric acid .

Reaction :

Zinc + dil. Sulphuric acid     →              Zinc sulphate + Hydrogen gas    

Zn + H₂(SO4)   →                      Zn (SO₄)  +H₂

                      

iv)Test of H₂ gas :When a burning splinter is introduced in a gas jar containing if splinter goes out while the gas burns a the mouth of the gas jar with pop sound and gas is hydrogen gas.

4.)Manufacture method of H₂ gas :

i) Methane gas is mixed with steam and allowed to react in presence of Ni to prepare H₂ to gas in manufacture scale .

       Methane + steam(water)       → ^Ni     Carbon monoxide + Hydrogen

CH₄ + H₂O      →^Ni           CO +3 H₂

ii)By electrolysis of water H₂ gas is prepared in manufacture scale .

 Water      → Electrolysis           Hydrogen + Oxygen

2H₂O   →Electrolysis              2H₂    +    O₂

5.)Properties :

Physical properties :

i)It is colourless ,odourless, and test less gas .

ii)It is the lightest gas .i.e. 22.2 liters of H₂ gas of wt only 2 gm .

iii)It is insoluble in water .

iv)It has no effect on an indicator .

Chemical properties:

i)When Hydrogen gas is burn in air ,water is obtained .

2H₂   +   O₂   →                    2H₂O

ii)When Hydrogen react with halogens i.e. Cl₂, Br₂,I₂,F₂,etc. and their respective halides are formed .

H₂   +  Cl₂                  →                            2HCl        

H₂     +   Br₂                 →                        2HBr      ❵      Hydrogen halides

H₂      +I₂                     →                           2HI

iii)When hydrogen react with Nitrogen at high temperature and high pressure Ammonia gas is obtained .This process is Haber’s process .

N₂  +3H₂             →       2NH₃

iv)When hydrogen combine with vegetable oil ,vegetable ghee is obtained .This process is known as hydrogenation .

H₂   +  vegetable oil               →           vegetable ghee

6.)Uses of H₂ gas :

i)It is used in manufacture of ammonia ,which is used making fertilizer .

ii)It is used for making vegetable ghee .

iii) It is used as fuel in rocket .

iv)It is used in welding and cutting  metal .

7.)Nascent Hydrogen :The newly born Hydrogen which is produced at the time of chemical reaction or very active hydrogen or hydrogen atom is called Nascent Hydrogen. It is denoted by H .Due to its highly reactive properties it immediately combine to Hydrogen to form Hydrogen molecules .

B .   Oxygen(O₂) gas

1.)Introduction :The symbol of oxygen is O,atomic N. 8,atomic weight 16 a.m.u., molecular formula O_2, and valency is 2 .It was first prepared by Joseph Priestley.It was named oxygen by Lavoisier

It is generally found in nature both free in air and combined state i.e. in water ,dissolve state ,in mineral combined state, and about 72% in our body as compound .

2.)General preparation of O₂ gas :

i)By Metal oxide :When metal oxide are heated and O₂ gas is produced .

2MgO              →      2Mg + O₂

2HgO               →      2Hg + O₂

2Ag₂O               →    4Ag + O₂

ii)By electrolysis of water :- Oxygen gas can be produced from decomposition of water by electrolysis method .

  H₂O             →         H⁺       +   (OH)^-

Reaction at cathode :

H⁺   +  e^-            →       H

4H            →    2 H₂

Reaction at anode :

(OH)^-           →       (OH) + e ^–

4(OH)         →      H₂O  +O₂

3.)Method of lab .preparation of O₂ gas :

A)By heating method :

i)Apparatus required :Hard glass test tube, delivery tube , gas jar, beehive self, heating apparatus.

ii)Chemical required : Potassium chlorate ,Manganese dioxide .

iii)Principle : O₂ gas can be prepared by heating K(ClO₃) in presence of MnO_2..

Reaction :

Potassium chlorate →                 Potassium chloride + Oxygen

2K(ClO₃)           →            2KCl     +3O ₂

iv.)Test of O₂ gas :When burning splinter is introduced in a gas jar containing  gas if gas burn more brightly and gas is Oxygen gas .because it is supporter of combustion.

b)Without heating method :

i)Apparatus required : Conical flask, thistle funnel, delivery tube ,Gas jar, Beehive self,

ii)Chemical required :Hydrogen peroxide, Manganese dioxide .

iii)Principle :O₂ gas can be prepared by  decomposition  Hydrogen peroxide in presence of manganese dioxide.

Reaction :

Hydrogen peroxide       →    MnO2      water + Oxygen

2H₂O₂ →  MnO2    2H₂O + O₂

4.)Manufacture method of O₂ gas :

i)By electrolysis of water :Large amount of O₂ gas is prepared by electrolysis of water in manufacture scale .

  H₂O               →       H⁺       +   (OH)^-

Reaction at cathode :

H⁺   +  e^-          →         H

4H             →   2 H₂

Reaction at anode :

(OH)^-           →       (OH) + e ^–

4(OH)          →     H₂O  +O₂

ii)From liquefied air :- To produce O₂ gas from liquid air in manufacture scale, at first air free from moister is liquefied by compression, cooling and sudden expansion method ,then air is allowed to vaporize ,so Nitrogen escape first due to lower boiling point i.e.-195⁰C and the remaining liquid is pure oxygen ,then finally O₂ is allowed to vaporize i.e. – 183 ⁰C and stored in cylinder .

5.)properties :

Physical :

i)It is colourless, odour less, and test less gas .

ii)It is slightly soluble in water i.e. about 3%

iii)It is does not burn but support to burn i.e. supporter to combustion.

iv)Chemical properties:

i)When oxygen is burn with hydrogen, water is obtained . 

  2 H₂ + O₂                  →      2H₂O

ii)When oxygen react with carbon dioxide is obtained .

   C  + O₂     →               CO₂

iii)When Oxygen combine with Nitrogen during lighting discharge  Nitric oxide is obtained .

N₂       +  O₂  →  ^Lighting            2NO    (Nitric oxide)

iv) When oxygen react with metal their respective metal oxide or base is obtained .

2Na + O₂     →         Na₂O

2Mg + O₂        →            2MgO                      Metal oxide or base

K +      O₂         →             K₂O

Fe  +   O₂        →      Fe₂O₃ (rust) 

6.) Uses of Oxygen:

I) It is used by living being for respiration .

ii)It is used for artificial respiration in hospital .

iii) Miners , Mountains, and sea divers carry oxygen cylinder with them for respiration .

iv)Liquid O₂ is used as a part of fuel in rocket and jet plane to make burning fuel .

C. Nitrogen Gas:

1.Itroduction : The symbol of Nitrogen is N, atomic N.7,atomic weight 15 a.m.u., molecular formula N_2, and valency is 2,and3 .It was discovered by Daniel Rutherford. It was named azote by Lavoisier, because it does not support for combustion and respiration .

It is generally found in nature both free in air and combined state i.e. in protein, and  Nitrate salt. 

2.Method of general preparation of N₂ gas:

i.)By heating of ammonia with copper oxide :When ammonia gas is prepared over heated copper oxide ,Nitrogen gas is obtained .

3CuO + 2NH₃               →          N₂ +3Cu +3H₂O

ii)By heating copper oxide in air :At first air is passed through lime water to eliminate  CO₂ ,then passed through conc. H₂( SO₄) to revolve moister and through cooper gauze to form CuO and from remaining as N₂ gas is obtained .

Cu +O₂                   →                2CuO

3.Lab preparation of N₂ gas :

i)Apparatus required :Round bottom flask ,Delivery tube, Thistle funnel ,Gas jar, Beehive self, heating apparatus .

ii)Chemical required :Sodium Nitrite ,Ammonium Chloride,

iii)Principle :N₂ gas is prepared by heating Na(NO₂) with (NH₄ )Cl.

Reaction :

Na(NO₂) + (NH₄)Cl  →         NaCl +2H₂O +N₂              

iv)Precaution :

i)The complete apparatus must be made air tight.

ii)The stem end of thistle funnel should be dipped under the solution .This prevent the escape of gas through thistle funnel .

v)Test of N₂ gas :If a burning splinter  is introduced inside the gas jar then they neither combustible nor support  for combustion and gas is N₂.

4.Methods of manufacture process of N₂ gas:

i)N₂ gas is prepared in manufactured scale by burning Cu in closed container of air then CuO and large amount of N₂ gas is produced in the  container .

2Cu +O₂                       →          2CuO

ii)N₂ and Oxygen gas is prepared in manufactured scale by liquefied air at very low temperature and pressure ,then due to different boiling temperature of these two gases Oxygen boils at -183⁰C and Nitrogen boils at -196⁰C and both gases are separately collected in cylinder .

5.Properties :

A) Physical properties :

i)It is colourless ,odourless and test less gas .

ii)It is lighter than that of air .

iii)It is slightly soluble in water .

iv) It is neither combustible nor supporter of combustion .

B)Chemical properties :

i)When magnesium  is react with Nitrogen ,magnesium Nitride is obtained .

3Mg + N₂            →    Mg₃N₂

ii)When Nitrogen is react with hydrogen under high temperature and high pressure ,ammonia gas is obtained .

N₂     +   3 H₂  →^{high pressure/temp}                  2NH₃

iii)At high temperature during lighting when Nitrogen react with Oxygen Nitric Oxide is obtained .

N₂       +    O₂   →  ^lighting                      2NO

6.Uses of N₂ gas :

i)It is used for making different fertilizer .

ii)It is used for making Nitric acid ,and ammonia gas .

iii)It is filled in filament to remove vaporization inside filament .

Unit :- 13                  Carbon and its compounds

Organic chemistry :The branch of chemistry concerned with the compounds of carbon is called organic chemistry .

Inorganic chemistry: The branch of chemistry concerned with the compound of elements other than carbon is called inorganic compound . 

Differences between organic and inorganic compound :

Organic compound	Inorganic compound
i.)The compounds of carbon other than oxides of carbon ,carbonates, bicarbonates, and carbides are called organic compounds .   ii.)Organic compounds having low melting and boiling points . iii.)Organic compounds burn easily .i.e. Ghee, alcohol  iv)These are formed by covalent bond. v.)Organic compounds are insoluble in water .	i.)The compounds other than compounds of carbon except oxides of carbon, carbonates ,bicarbonates ,and carbides are called inorganic compounds. ii.)Inorganic compounds having high melting and boiling points iii)Inorganic compounds do not burn easily . i.e. salt iv)These  are formed by electrovalent bond. v)Inorganic compounds are soluble in water .

Carbon :Its symbol is C ,atomic number 6,atomic weight 12 and valency 4 .It is derived from Latin word carbo  which means charcoal .It is found in the nature various form i.e. CO₂ ,Coal , charcoal, graphite ,diamond  etc.

Sources of carbon :

i.)It is found in atmosphere in the form of CO₂ .

ii)It is found in all living being in the form of compounds .

iii.)It is found in the form of carbonate, and bicarbonate  compounds .

iv)It is found in natural hydrocarbon i.e. coal ,Petroleum, and natural gas .

Nature of carbon :  Carbon atoms has 4 valence electrons to their valence shell ,so it can loss or gain 4 electrons to become stable but the size of the carbon atom is smaller,so effective nuclear charge is strong and strongly hold valence electrons .Hence It can neither loss nor can gain electrons and can not form electrovalent bond .Therefore it form 4 covalent bond by sharing its 4 valence electrons with other atoms . 

 

Allotropes :The property of a pure element having same composition but found in two or more than two forms in the same state is called allotropes .For example :

                                                  Allotropes of carbon

Catenation: The ability of carbon to combine with another carbon atoms to long chain of or ring of different size is called catenation .

Properties of carbon :

Physical properties of carbon :

i)It is found in solid state and non metal .

ii.)It is insoluble in water .

iii)It show allotropic properties .

iv)It is generally black in colour but diamond is colourless and transparent .

Chemical properties :

i)When carbon burn with sufficient oxygen ,carbon dioxide is obtained but with insufficient oxygen carbon monoxide is obtained.

C+O₂   →            ^sufficient            CO₂

2C  `+ O₂    →        ^insufficient          2CO

 

ii)When carbon react with steam at high temperature ,carbon monoxide and hydrogen gas or water gas

C   + H₂O   →                  CO+H₂

                                     _{Water gas}

Diamond :Diamond is a giant (more luminous) covalent structure in which:

·         each carbon atom is joined to four other carbon atoms by strong covalent bonds

·         the carbon atoms form a regular tetrahedral network structure or three dimensional structure.

·         there are no free electrons

.

Properties and uses

i.)The rigid network of carbon atoms, held together by strong covalent bonds, makes diamond very hard.

ii)A pure diamond is colourless ,transparent and solid but presence of some amount of impurities some diamond are coloured i.e. yellow, orange ,red, brown, and black but black is very hard .

iii)It is very poor conductor of heat and electricity .

iv)It is insoluble in all liquids.

Uses:

i)it useful for cutting tools, such as diamond-tipped glass cutters.

ii)It is used for making precious gems and jewellery .

iii)It is used by eye surgeons to remove cataract from eye .

 Graphite :Graphite has a giant covalent structure in which:

each carbon atom forms three covalent bonds with other carbon atoms

·         the carbon atoms form layers of hexagonal rings

·         there are no covalent bonds between the layers

·         there is one non-bonded - or delocalised – electron from

each atom.

·         Dotted lines represent the weak forces between the layers in graphite

 

Properties :

i.)Graphite has delocalised electrons, just like metals.

ii.)These electrons are free to move between the layers in graphite, so graphite can conduct electricity or good conductor of heat and electricity..

iii)The forces between the layers in graphite are weak. This means that the layers can slide over each other. This makes graphite slippery, so it is useful as a lubricant.

iii)It is black or brown in colour.

iv)It is very soft.

Uses :

i)It is used as electrodes because it is a good conductors of electricity.

ii.)Due to its soft and slippery characters ,it is used as a good dry lubricant for those parts of machines where grease and oil can not be used.

iii)It is soft and black in colour so it used for making the cores of lead pencils.

Uses of carbon :

i.)Carbon is used as fuel .

ii.)Charcoal is used for purifying drinking water ,decolourlizing  sugar .

iii)Lamp black is used in the printers ,manufacture of polish,black paints .etc .

Hydrocarbon :The compounds hydrogen and carbon is called hydrocarbon.

Types  of hydrocarbon :They are two types :

A.)Saturated hydrocarbon :The hydrocarbon in which carbon-carbon atoms combines with single covalent bond are called saturated hydrocarbon .Its IUPAC(International union pure applied chemistry ) name is alkane  For example :

B.)Unsaturated hydrocarbon :The hydrocarbon in which carbon atoms combine with double covalent bond is called unsaturated hydrocarbon.Its  IUPAC (International union pure applied chemistry ) name is Alkene .For example :

  Unit :- 14            Water

Water: A substance composed of the chemical elements hydrogen and oxygen is called water .It is found  in gaseous, liquid, and solid states. It is one of the most plentiful and essential of compounds.  it has the important ability to dissolve many other substances

Sources of water: There are two main sources of water: 

1.)surface water :The sources of water which are present on the surface of the earth are called surface resources of water .For example : , rivers, lakes, wetlands, reservoirs, spring, ponds, lakes.sea water ocean water are the example of surface water .

Groundwater: The sources of water which is present   underground in the cracks and spaces in soil, sand and rock is called ground water. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers

Physical properties of water

i)It is a colourless, odourless and tasteless liquid

ii).It is an excellent solvent.

iii)The boiling point of water is 100⁰C and freezing of water is 0⁰C .

iv)At 4⁰C water has maximum density and minimum volume .Chemical properties of water

1)Amphoteric nature:

Water can act as both acid and base, which means that it is amphoteric    in         nature.
Example: 

i)NH₃+     H₂O           →         NH₄+       +       OH^-

base         acid

ii) HCl  +      H₂O        →        H₃O⁺         +          Cl^-

  acid          base

2)Reaction with alkali metal :When water  react with alkali metal  oxide and hydrogen gas is obtained .

i)Na + H₂O              →            Na₂O  + H₂

ii)Mg + H₂O                 →        MgO  +H₂

Uses of water : It is used for following purpose :

1)Domestic uses of water: 15 % of water is consumed for domestic purpose. It is used for drinking, bathing, cooking food and washing dishes, clothes, fruits, vegetables and brushing teeth.

2.)Water use for agriculture : 70% of water is used for agriculture. It  is used for gardening, farming and fisheries. Plants require water to grow. During the process of photosynthesis, they consume water. To yield crops, fruits, flowers, vegetables they need sufficient water, manure, sunlight and oxygen.

3)Industrial uses of water: It is e used for creating or to cool the equipment ,washing, cooling, processing, transporting, diluting or fabricating of a product. The maximum amount of water is used in the production of chemical, paper and food.

Types of water :There are two types of water

1.)Soft water : The water which gives lather easily with soap is called soft water .

For example :Rain water ,distilled water etc.

2.)Hard water :The water which does not produce lather easily with soap is called hard water . For example :Underground water ,water of stream, river etc.

                             Causes of hardness of water :Hardness of water caused by presence of following soluble salts i.e.

 i)Calcium bicarbonate=Ca(HCO₃) ₂              〕      i)Temporary

 ii)Magnesium bicarbonate =Mg(hCO₃)_{2       〕}  hardness

iii)Calcium chloride =CaCl₂ ,

iv) Magnesium chloride =MgCl₂       〕            ii)Permanent

 v)Calcium sulphate =Ca(SO₄)          〕            hardness

  vi) Magnesium sulphate =Mg(SO₄     )

 Types of hardness of water :There are two types of hardness of water :

i)Temporary hardness of water :The hard water caused by the presence of soluble salts i.e. Calcium bicarbonate , and Magnesium bicarbonate is called temporary hardness of water .

ii)Permanent hardness of water :The hardness of water caused by the presence of soluble salt i.e. Calcium carbonate ,Magnesium carbonate ,Calcium chloride and Magnesium carbonate is called permanent hardness of water .

Methods of removal of temporary hardness of water :Temporary hardness of water can be removed by following two methods :

i)By boiling :The temporary hardness of water can be removed by boiling of water because due to boiling soluble  bicarbonate salts are converted into insoluble carbonates which can be removed later by filtration. For example :

Ca(HCO₃)          →       ^Boil                 Ca(CO₃) +CO₂+H₂O

 ii)By using lime water :Temporary hardness of water can be removed by treating with calculated amount of lime ,because due to lime water soluble bicarbonate salts are converted into insoluble carbonates ,which can be removed by later filtration .This process is known as clark’s method.

For example :

Ca(HCO₃)₂ +Ca(OH)₂           →             2Ca(CO₃) + 2H₂O

Methods of removal of Permanents hardness of water: Permanents hardness of water can be removed by following two methods :

i)By adding washing soda(Sodium Carbonate): Permanent hardness of water can be removed by adding washing soda because it convert soluble chloride and sulphate of Magnesium and Calcium salts into insoluble form which can be removed later by filtration .For example:

i)CaCl₂ +Na₂(CO₃)    →                Ca(CO₃)+NaCl

                ^{washing soda                         insoluble form}

ii)Mg(SO₄) +Na₂(CO₃)   →    Mg(CO₃)+Na₂(SO₄)

                     ^{washing soda           insoluble form}

ii)By Permutit Method : Permutit is the trade name for an artificially prepared sodium zeolite or sodium aluminium orthosilicate obtained by fusing together sodium carbonate silica and alumina(Na₂ Al₂ Si₂ O_8.xH₂O).  It possesses the higher quality of reactivity with calcium and magnesium ions forming insoluble calcium or magnesium zeolites

Ca⁺⁺  + Na₂Z     →            CaZ +2Na⁺

Mg⁺⁺  + Na₂Z   →          MgZ +2Na⁺

Calcium and Magnesium Zeolites being insoluble remains in the tower and soft water free from calcium and magnesium salts is above the permutit .

Advantages of hard water :

i)It contains minerals i.e. calcium and iron that help to maintains strongest of teeth and bones of our body.

ii)Hard water has a better flavor than that of soft water due presence of minerals .

iii)Hard water can minimize the chances of heart diseases .

Disadvantages of hard water :

i)Hard water consumes more soap due to less lather .

ii)Hard water is not fit for washing white clothes .

iii)Hard water is not good for water tanks because it reduces the life span period of tanks .

Unit :-15  Chemical fertilizers used in Agriculture

Fertilizer :The substances which are added to increase the fertility of soil or  increase to  crops production are called fertilizer .

Types of fertilizers :-They are two types :

1)Organic fertilizers: The fertilizers which are obtained from dead and decomposed parts of animals and plants or their waste product are called organic fertilizer . There are also two types of organic fertilizers :-

i)Green organic fertilizers :The organic fertilizer which are prepared by cutting green plants and later which are decomposed under soil are called green organic fertilizer or green manure .These types of fertilizer mainly provides  nitrogen  to the plants in form of nitrates .

ii)Animal organic fertilizer :-The organic fertilizer which are prepared from dead and decayed parts of animals due to the action of bacteria and enzymes in their body are called animal organic fertilizer .It do not contain nitrogen ,phosphorus and potash but can control weeds and increases the moisture-holding capacity of the soil and increases air penetration in the soil.

Advantages of organic fertilizers :

i.)It help to Balances the soil ecosystem

ii)It help plant to make health naturally

iii)They’are all-natural .

iv)It increase the fertility of soil.

 v)It does not  affect the quality of soil.

vi)It controls environmental pollution.

 vii)Prevents from  over-fertilization

Disadvantages of organic fertilizers:

i)It requires more  time to be  prepared. so effectiveness is limited seasonally.

ii)It is insoluble in water and it is difficult to transport from one place to another place .

iii) Nutrients ratio is always unknown .

2.)Chemical fertilizers or inorganic fertilizers: The fertilizer which are made by mixing different  of chemicals substances are called chemical fertilizers .They are mainly contains nitrogen, phosphorus and calcium elements.

N.P.K fertilizers :The fertilizer containing  all three nutrients i.e. Nitrogen(N) ,Potassium (K) and calcium(Ca) essential for plants is called NPK fertilizers .It is also called complete fertilizer.

 Advantages of chemical or inorganic fertilizers :

i)Inorganic  fertilizer increase the fertility of the soil.

ii)They have special types of nutrients .

iii)They can transport easily .

iv)They are water soluble ,so plants can absorb easily .

Disadvantages of inorganic or chemical  fertilizers :

i)Inorganic fertilizer pollute the environments.

ii)Inorganic fertilizers increase the fertility of the soil.

Considering factors or  precaution  while using chemical fertilizers :

i)Before the use of chemical fertilizers, we must test the acidic or basic nature of soil.

ii)At the time of using chemical fertilizers ,we must cover our mouth and nose .

iii)we must control the flow of chemical fertilizers in sources of water .

iv)Chemicals fertilizers should be used scientifically ,in term of proper dose   and time ,because excessive use  of fertilizer can harm plants instead of better growth .

Some important inorganic fertilizers :

1.)Nitrogeneous  fertilizer :The chemical fertilizer that supply nitrogen to plants are known as nitrogeneous fertilizer For example :

i)Urea (NH₂CONH₂)

ii)Ammonium suplhate  (NH₄)₂(SO₄)

iii)Ammonium nitrate (NH₄)(NO₃)

Functions of Nitrogen :

i)It help in rapid growth in plants .

ii)It help to increase yield of growth .

iii)Sufficient nitrogen help for high rate of photosynthesis .

iv)It help in the formation of chlorophyll ,carbohydrate, and protoplasm .

Deficiency of Nitrogen :

i)Due to lack of nitrogen plants will be shorter ,leaves may be smaller and maturity of plants may be delayed too .

ii)Shortage of nitrogen will causes of yellowing of leaves .

iii) Due to lack of nitrogen rate of photosynthesis will decreases and less branching in plants .

2.)Phosphatic  fertilizer :The fertilizers that supply phosphorus to the plants are called phosphatic fertilizers .For example :

i)Calcium super phosphate

ii)Triple super phosphate

iii)Bone metal .

Functions of Phosphorus :

i)It help in early maturity in plants .

ii)It help in formation and fast growth of root .

iii)It help in formation of seeds and increase resisting diseases .

Deficiency  of phosphorus :

i)Due to lack of phosphorus flowering may be delayed .

ii)Due to lack of phosphorus rate of cell division decreases .

iii)Due to lack of phosphorus reduces diseases resistant power of the plants .

3.)Potash fertilizers :The fertilizers that supply potassium to plants are known potash fertilizers .For example :

i)Potassium chloride (KCl)

ii)Potassium sulphate  K₂(SO₄)

iii)Potassium carbonate K ₂(CO₃)

iv) Potassium Nitrate    K (NO₃)

Functions of potassium :

i)It help in the utilization of nitrogen and help in protein synthesis .

ii)It help for making healthy roots and shoots .

iii)It also help to increase resist against diseases

iv)It help to regulates the opening and closing of stomata . 

Deficiency of potassium :

i)Lack of potassium causes of poor resistance for  diseases.

ii)Lack of potassium causes of weak roots and shoots.

iii)Lacks of potassium causes of losing of leaves .