S.No	Mole	Molar Mass
1	It is defined as the amount of the substance that contains as many specified elementary  particles as the number of atoms in 12g Of CI2	It is defined as the mass of one mole of the substance
2	1 mole = 6.023 x 1023	Molar mass = \(\frac { mass }{ mol } g{ mol }^{ -1 }\)

No, one gram mole of a gas occupies 22.4 L only under S.T.P conditions, i.e. at 273 K temperature and 760mm of pressure

Avogadro's law. It states equal volumes of all gases under the same conditions of temperature and pressure contain equal number of molecules

Atomicity of an elementary substance is defined as the number of atoms in a molecule of the element.

(a) 1 gram molecule of sugar = 342 g
\(\therefore\)  0.5 g molecule of sugar = 342 x 0.5
= 171 g
(b) 342 g of sugar = I gram molecule
547.2 of sugar = \(\frac { 1 }{ 342 } \times 547.2\)
= 1.6 gram molecule

Molecular mass of Sugar C₁₂H₂₂O₁₁
= 12 x 12 + 22 x 1 + 11 x 16 = 342

Equivalent weight of H₃PO₄
= \(\frac { Molecular\ mass }{ No.of\ replaceable\ { H }^{ + } } =\frac { 98 }{ 1 } =98\)
Equivalent weight of Ca(OH)₂
= \(\frac { Molecular\ mass }{ No.of\ replaceable\ {O H }^{ - } } =\frac { 74 }{ 1 } =74\)

The reaction is
N₂ + 3H₂ \(\longrightarrow\) 2NH₃
1mol  3mol       2 mol
2 x 14 = 2(1 x 14 + 3 x 1)
28 g = 34 g
Thus, to produce 34.0 g ammonia, 28 g of N₂ is required

NO₃^-
x + 3(-2) = -1
x - 6 = -1
x = -1 + 6
x = +5
Oxidation number of N in NO₃^- is +5

K₂CrO₄
2(1) + x + 4(-2) = 0
2 + x - 8 = 0
x - 6 = 0
x = +6
Oxidation number of Cr in K₂CrO₄ is +6

K₂MnO₄
Oxidation number of Mn be x
2 (1) + x + 4 (-2) = 0
2 + x - 8 = 0
x - 6 = 0
x = 6
Oxidation number of Mn in K₂MnO₄ is +6

Oxygen
Mass of oxygen atom = 2.656 x 10^-23 gram
1 amu = 1.6605 x 10^-24g
The mass of oxygen atom in amu = \(\frac { 2.656\times { 10 }^{ -23 } }{ 1.66056\times { 10 }^{ -24 } } \approx 15.99\quad amu\)

Al₂(SO₄)₃ + 3 BaCl₂ \(\longrightarrow\) 3 BaSO₄ + 2 AlCl₃
When 1 mole of aluminium sulphate reacts with barium chloride, 3 moles of BaSO₄ is precipitated.

(i) Nitrous acid: HNO₂
+ 1 + x - 2 x 2 = 0
x = +3
(ii) Nitric acid: HNO3
+ 1 + x - 2 x 3 =0
x = +5.

1 x AW of Mg = 1 x 24.305 = 24.305 amu
2 x AW of O = 2 x 16 = 32.000 amu
2 x AW of H = 2 x 1.008 = 2.016 amu
Formula weight of Mg(OH)₂ is = 58.321 amu
Formula weight of Mg(OH)₂ is = 58 amu.

1 x AW of Na = 1 x 22.99 = 22.99 amu
1 x AW of O = 1x 16 = 16.00 amu
1 x AW of H = 1 x1.008 = 1.008 amu
Formula weight of NaOH is = 39.998 amu

6 x AW of C = 6x12.01 = 72.06 amu
12 x AW of H = 12x1.008 = 12.096 amu
6 x AW of O = 6 x16 = 96.0 amu
Formula weight of Glucose is = 180.156 am

1 x AW of N = 1 x 14 = 14amu
2 x AW of O = 2 x16 = 32 amu
Formula weight of NO₂ = 46 amu

Molar mass of H₅IO₆ = (5x1 + 1x127 + 6x16)
= 228 g mol^-1
Mass of 5.14 mol of H₅IO₆ =5.14 mol x 228g mol^-1
= 1171.9 g.

Molar mass of CO₂ = (1 x 12 + 2 x 16)
= 44 g mol^-1
Mass of 3 moles of CO₂ = 3 mol x 44g mol^-1
= 132 g

Molar mass of NH₃ = (1 x 14 + 3 x 1) = 17g mol^-1
Mass of 0.2 mol of NH₃ = 0.2 mol x 17g mol^-1
= 3.4 g

No. of silver atoms = 1 million = 1 x 10⁶
Mass of one million Ag atoms = 1.79 x 10^-16g
Mass of 6.023 x 10²³atoms of silver
= \(\frac { 1.79\times { 10 }^{ -16 }g }{ 1\times { 10 }^{ 6 } } \times 6.023\times { 10 }^{ 23 }\)
= 107.8 g.
Atomic mass of silver = 6.023 x 10²³ atoms of Ag
\(\therefore\)  The atomic mass of Ag = 107.8 g

Molecular mass of water = (2 x 1u) + (1 x 16u)
= 18 u
Molar mass of water = 18 g mol^-1
Mass of 1 molecule of water
= \(\frac { Molar\ mass\ of\ water }{ Avogadro's\ number } \)
= \(\frac { 18\ g\ { mol }^{ -1 } }{ 6.023\times { 10 }^{ 23 }\ { mol }^{ -1 } } \)
= 2.99 x 10^-23 g
Mass of 1 molecule of water = 2.99 x 10^-23 g

Molecular mass of benzene (C₆H₆) = (6 x 12.01 u) + (6 x 1 u) = 78.06 u
Molar mass of benzene = 78.06 g mol^-1
Then, mass of [molecule of benzene = \(\frac { Molar\ mass }{ Avogadro's\ number } \)
= \(\frac { 78.06g\ { mol }^{ -1 } }{ 6.023\times { 10 }^{ 23 }\ { mol }^{ -1 } } \)
= 12.96 x 10^-23 g

Molecular mass of silver (Ag) = 107.87 u
Molar mass of Ag = 107.87 g mol^-1
\(\therefore\) Mass of 1 atom of Ag = \(\frac { Molar\ mass }{ Avogadro's\ number } \)
= \(\frac { 107.87g\ { mol }^{ -1 } }{ 6.023\times { 10 }^{ 23 }\ { mol }^{ -1 } } \)
= 17.91 x 10^-23g
Mass of 1 atom of Ag = 17.91 x 10^-23 g.

52g of He contains 7.83 x 10²⁴ He atoms.
1 mol of He contains 6.023 x 10²³ He atoms
\(\therefore\) 52 moles of He contains =  \(\frac { 6.023\times { 10 }^{ 23 }\times 52 }{ 1} \)
= 3.132 x 10²⁵
52 moles of He contains 3.132 x 10²⁵ He atoms

1 mol of He \(\equiv\) 4g \(\equiv\) 6.022 x 10²³ He atoms
(ie) 4g of He contains 6.022 x 10²³ He atoms
\(\therefore\) 52g of He contains = \(\frac { 6.023\times { 10 }^{ 23 }\times 52 }{ 4 } \)
= 7.83 x 10²⁴

Chemical Classification:
1) Matter can be classified into mixtures and pure substances based on chemical compositions.
2 ) Mixtures consist of more than one chemical entity present without any chemical interactions. They can be further classified as homogeneous or heterogeneous mixtures based on their physical appearance
3) Pure substances are composed of simple atoms or molecules. They are further classified as elements and compounds.
(a) Element:
1) An element consists of only one type of atom.
2) Element can exist as monatomic or polyatomic units. The polyatomic elements are called molecules  
3) Eg: Monatomic unit - Gold (Au), Copper (Cu); Polyatomic unit- Hydrogen (H₂)
(b) Compound:
1) Compounds are made up of molecules which contain two or more atoms of different elements.
2) Properties of compounds are different from those of their constituent elements.
3) Eg: Carbon dioxide (CO₂), Glucose (C₆H_I2O₆)

Physical Classification of Matter : Matter can be classified as solids, liquids and gases based on their physical state. The physical state of matter can be converted into one another by modifying the temperature and pressure suitably.

Two or more substances mix together in any ratio without any chemical interaction is called mixture.
(i) Homogeneous mixture :
A mixture having a uniform composition throughout is called homogeneous mixture.
Eg: salt solution, air etc.
(ii) Heterogeneous mixture :
A mixture in which the composition is not uniform throughout and different components can be observed is called heterogeneous mixture. Eg : Mixture of salt and sugar, cereals and pulse etc.,

	ELEMENTS	COMPOUNDS
(i)	An element consists of only one type of atom	Compounds are made up of molecules which contain two or more atoms of different elements.
(ii)	Element can exist as monatomic or polyatomic units. The polyatomic elements are called molecules	Properties of compounds are different from those of their constituent elements.
(iii)	Eg : Monatomic unit - Gold (Au), Copper (Cu);  Poly atomic unit -  Hydrogen (H2)	Eg: Carbon dioxide (CO2), Glucose (C6H12O6)

Compound

Air sometimes considered as a heterogeneous mixture due to the presence of dust particles which form a separate phase.

The solution is a homogeneous mixture of two or more components. Salt in water is homogeneous and therefore it is a solution. Whereas oil in water is heterogeneous or immiscible mixture and so is not a solution

Distilled water molecules contain only H₂O It is a pure substance so a compound. Tap water usually contain impurities such as dust so it is a mixture

The properties used to identify a substance are colour, density, melting point and boiling point etc

'X' is a mixture since elements and compounds are pure substance.

(i) In reactions, (i) & (ii) AgNO₃ and CuSO₄ act as oxidising agents. They oxidise H₃PO₂ (hypophosphorous acid) to (orthophosphoric acid)
(ii) In reaction (iii) [Ag (NH₃)₂]⁺ _(aq) oxidises C₆H₅CHO to C₆H₅COOH.
(iii) In reaction (iv) Cu²⁺ does not oxidise C₆H₅ to C₆H₅COOH.
(iv) This indicates that Ag⁺ is a strong oxidising agent than Cu.

The oxidation state of CI in ClO₂^- is +3. So, chlorine can get oxidised as well as reduced and can act as reductant and oxidant.
The disproportionation reaction of ClO₂^- is
\(\begin{matrix} +1 \\ 3Cl{ O }_{ 2 }^{ - } \end{matrix}\longrightarrow { Cl }^{ - }+\begin{matrix} +5 \\ Cl{ O }_{ 3 }^{ - } \end{matrix}\)
In CIO₄^- , CI is in its highest oxidation state, So it can only be an oxidant.

(i) Nitric acid in an oxidising agent. It oxidises an element from lower oxidation state to the higher oxidation state In PbO, lead is in lower oxidation state of +2. HNO₃ oxidises lead from Pb²⁺ to  Pb⁴⁺
PbO + 2HNO₃ \(\longrightarrow\) Pb (NO₃)₂ + H₂O
(ii) In PbO₂, lead is in +4 oxidation state and cannot be oxidised further. Therefore no reaction takes place.

1. The blue colour of CuSO₄ solution will get discharged and reddish brown copper metal will be deposited on Zn rod.
2. This is because blue colour Cu²⁺ (in CuSO₄) gets reduced to Cu by accepting two electrons from Zn, which gets oxidised to colourless ZnSO₄.

At the anode, loss of electron takes place (ie.,) oxidation occurs. Hence called as oxidation electrode.
At the cathode, the gain of electrons takes place (ie.,) reduction occurs. Hence called as reduction electrode.

In a redox reaction, the total number of electrons lost by the reducing agent must be equal to the number of electrons gained by the oxidising agent.

1. If H⁺ any acid appears on either side of the chemical equation, the reaction occurs in acidic solution.
2. If OH^- or any base appears on either side of the chemical equation, the reaction occurs in basic solution.
3. If neither H⁺, OH^- nor any acid or base is present in the chemical equation, the solution is neutral.

(i) Oxygen is being added to Cu, (ie.,) Cu₂S is oxidised to Cu₂O and the other reactant O₂ is getting reduced
(ii) Cu₂S is the reducing agent.
O₂ is an oxidising agent.

1. Fading of the colour of the clothes 
2. Burning of cooking gas, fuel, wood, etc.
3. Rusting of Iron
4. Extraction of Metals

In MnO₄^2-, Mn is in the highest oxidation state (ie) +7. Therefore, it does not undergo disproportionation. MnO₄^2- undergoes disproportionation as follows :
3MnO₄^2- +4H⁺\(\longrightarrow\) 2MnO₄^- + MnO₂ + 2H₂O
In MnO₄^2-, the oxidation state of Mn is +6. It can disproportionate to form MnO₂ and MnO₄

Lewis acid : H⁺, BF_3, Ni²⁺
Lewis Base : S^2-, OH^-, F^-

Equal volumes of all gases under the same conditions of temperature and pressure contain equal number of molecules.

The volume occupied by one mole of any substance in the gaseous state at a given temperature and pressure is called molar volume.

The total number of entities present in one mole of any substance is equal to 6.022 x 10²³. This number is called Avogadro number.