Monday, 24 February 2025

Chemistry passing package

     10th Science Most Important Repeated Concepts

       ๐—ฃ๐—ฎ๐˜€๐˜€๐—ถ๐—ป๐—ด ๐—ฃ๐—ฎ๐—ฐ๐—ธ๐—ฎ๐—ด๐—ฒ    

          ๐—–๐—ต๐—ฒ๐—บ๐—ถ๐˜€๐˜๐—ฟ๐˜†         

         ๐—–๐—ต๐—ฒ๐—บ๐—ถ๐—ฐ๐—ฎ๐—น ๐—ฅ๐—ฒ๐—ฎ๐—ฐ๐˜๐—ถ๐—ผ๐—ป๐˜€ ๐—ฎ๐—ป๐—ฑ ๐—˜๐—พ๐˜‚๐—ฎ๐˜๐—ถ๐—ผ๐—ป๐˜€         

โ†’Chemical reaction 

โ˜… Reactant converted into product.

โ†’Chemical equation 

โ˜… Symbolically representation of chemical reaction. 

โ†’Balanced chemical equation

โ˜… Same number of atoms in LHS and RHS 

Important balanced Chemical equations 

โ˜… Na2SO4 + BaCl2 โ†’ BaSO4+ 2NaCl

โ˜… CaCO3 โ†’  CaO + CO2

โ˜… H2 + Cl2 โ†’ 2HCl

โ˜… 2Na + 2H2O โ†’ 2NaOH +H2

โ˜… CaO(s) + H2O(l) โ†’ Ca(OH)2

โ˜… Mg + 2HCl โ†’ MgCl2 + H2

โ˜… CH4(g) + 2O2(g) โ†’ 2H2O(g) + CO2(g) 

โ†’ Combination reactions 

โ˜… Two reactants โ†’one product

Ex: H2 + Cl2 โ†’2HCL

โ†’ Decomposition reaction 

โ˜… One reactant โ†’ two or more products 

Ex: CaCO3 โ†’ CaO + CO2

โ†’ Electrolytic decompositin (Electrolysis of water)

โ˜… Cathode - H2

โ˜… Anode - O2

โ†’  Photolytic decomposition

Ex: 2AgCl โ†’  2Ag + Cl2 

โ†’ Oxidation 

โ˜… Addition of oxygen 

Ex: 2Zn + O2 โ†’2ZnO

โ†’ Reduction 

โ˜… Removing of oxygen 

Ex: ZnO + C โ†’Zn + CO

โ†’ Redox reaction 

โ˜… Oxidation and reduction occur in same reaction.

Ex: CuO + H2  โ†’  Cu  + H2O

โ†’ Displacement reaction 

โ˜… More reactive element displace the less reactive element.

Ex: Fe + CuSO4 โ†’ FeSO4

Iron more reactive than copper.

โ†’ Double displacement reaction 

โ˜… Exchange of ions between reactants.

Ex: Na2SO4 + BaCl2 โ†’ BaSO4 + 2NaCl

โ†’ Precipitation reaction 

โ˜…  Insoluble substance formed in the reaction 

Ex: Na2SO4 + BaCl2 โ†’ BaSO4 + 2NaCl

Precipitate - BaSO4

Ions - Ba^2+ and SO4 ^ 2-

โ†’ Exothermic reaction 

โ˜… Heat released in the reaction 

Ex: CaO + H2O โ†’  Ca(OH)2   +   Heat

โ†’ Endothermic Reaction 

Heat absorbed in the reaction 

Ex: CaCO3 โ†’CaO + CO2

โ†’ Corrosion 

โ˜… Metal + atmosphere substance โ†’ Undesirable substance 

Ex: Rusting of iron  

โ†’ Rancidity 

โ˜… Smell /taste of oil/fat containing substance change by oxidation.

Prevention 

โ˜… Use Antioxidant 

โ˜… Refrigerating.

โ˜… Use Nitrogen gas

โ˜… Pack in air tight container 

โ†’ Important Oxidised and Reduced reactants.

โ˜… Na + O2 โ†’Na2O

Oxidized substance - Na

Reduced substance - O2

โ˜… CuO + H2 โ†’ Cu + H2O

Oxidized substance - H2

Reduced substance - CuO

โ˜… ZnO + C โ†’ Zn + CO

Oxidized substance - C

Reduced substance - ZnO

         ๐—”๐—ฐ๐—ถ๐—ฑ๐˜€, ๐—•๐—ฎ๐˜€๐—ฒ๐˜€ ๐—ฎ๐—ป๐—ฑ ๐—ฆ๐—ฎ๐—น๐˜๐˜€        

โ†’ Acid.

โ˜… Sour taste 

โ˜… Produce H+ ions

โ˜… Blue litmus to red

โ˜… pH below 7

โ˜… Ex: HCl, H2SO4

โ†’Base 

โ˜… Bitter taste 

โ˜… Produce OH- Ions

โ˜… Red litmus to blue 

โ˜… pH above 7

โ˜… Ex: NaOH, KOH,  Ca(OH)2...

โ†’Reactions 

โ˜… Acid + Metal โ†’ Salt + Hydrogen gas

Ex: H2SO4 + Zn โ†’ ZnSO4 + H2

โ˜… Acid + Metal carbonate โ†’ Salt + water + Carbon dioxide 

Ex: HCl + NaHCO3 โ†’NaCl + H2O + CO2

โ˜… Acid + Metal oxide โ†’ Salt + Water 

2HCl + ZnO โ†’ZnCl2 + H2O

Neutralization reaction 

โ˜… Acid + Base โ†’Salt + Water 

Ex: NaOH + HCl โ†’NaCl + H2O

โ†’ Some naturally occurring acids

โ˜… Vinegar  - Acetic acid

โ˜… Orange - Citric acid

โ˜… Tamarind - Tartaric acid

โ˜… Tomato - Oxalic acid

โ˜… Sour milk (Curd) - Lactic acid

โ˜… Nettle sting - Methanoic acid

โ˜… Ant sting - Methanoic acid

โ˜… Lemon - Citric acid

โ†’Tooth decay 

Causes 

โ˜… In our mouth, bacteria convert sugar into acid 

โ˜… This acid cause tooth decay

Prevention 

โ˜… Use toothpaste which is basic and it neutralize the acid

Blood pH: 7.2 to 7.8

Acid rain pH: below 5.6

โ†’ Chloro alkali process 

2NaCl + 2H2Oโ†’ 2NaOH + Cl2 + H2 

Product uses:

NaOH

โ˜… Soaps and detergents

โ˜… Papar making 

Cl2

โ˜… Water treatment 

โ˜… Swimming pool

โ˜… PVC

H2

โ˜… Fuels

โ˜… Margarine 

โ†’ Washing Soda

โ˜… Chemical name - Sodium carbonate 

โ˜… Chemical formula -Na2CO3

Uses 

โ˜… Manufacture of borax, 

โ˜… softening of hard water

โ†’Baking Soda

โ˜… Chemical name - Sodium hydrogen carbonate 

โ˜… Chemical formula -NaHCO3 

Uses -

โ˜… antacid

โ˜… ingredient of baking powder

โ†’ Bleaching Powder 

โ˜… Chemical name - Calcium oxychloride 

โ˜… Chemical formula -CaOCI2 

Uses -

โ˜… Bleaching clothes

โ˜… oxidizing agents

โ˜… disinfecting water 

โ†’ Plaster of Paris 

โ˜… Chemical name - Calcium sulphate Hemihydrate 

โ˜… Chemical formula -CaSO4.1/2H2O 

Uses -

โ˜…  Fractured bones 

โ˜… Making toys 

โ˜… Decorative materials

         ๐— ๐—ฒ๐˜๐—ฎ๐—น๐˜€ ๐—ฎ๐—ป๐—ฑ ๐—ก๐—ผ๐—ป-๐— ๐—ฒ๐˜๐—ฎ๐—น๐˜€        

โ†’ Physical properties of Metals

โ˜… Sonorous 

โ˜… Ductile 

โ˜… Malleable 

โ˜… Lustrous 

โ˜… Conduct heat and electricity 

โ†’ Physical Properties of Non-Metals

โ˜… No sonorous 

โ˜… No ductile 

โ˜… No malleable 

โ˜… Poor conductor of electricity 

Ductile : Metal can drawn in to thin wire.

Malleable : Metal can beaten in to thin sheet.

โ†’ Chemical properties of metals :

โ˜… Liberates H2 from dilute acids.

โ˜… Metallic oxides are basic in nature. 

โ†’ Chemical properties of non-metals :

โ˜… Do not liberate H2 from dilute acids. 

โ˜… Oxides of non-metals are acidic in nature. 

โ†’ Formation of NaCl

โ†’ Formation of MgCl2

โ†’ Properties of ionic compounds 
โ˜… Hard and brittle.                
โ˜… High melting points and high boiling points [ because strong force of attraction between ions]   
โ˜… Soluble in water but insoluble in organic solvents.   
โ˜… Conduct electricity in solution or molten state. [Not conduct electricity in solid state because ions are fixed cannot move]

โ†’ Extraction of Zn

Roasting:
                   Heat 
ZnS + O2    โ†’    ZnO  + SO2

Calcination:
               Heat
ZnCO3    โ†’   ZnO + CO2

Reduction:

ZnO  +  C   โ†’  Zn  +  CO

Calcination:
                     Heating strongly 
Carbonate ore        โ†’       Oxides 
                           Limited air

Roasting:

                      Heating strongly 
Sulphide ore          โ†’         Oxides 
                           Limited air

โ†’ Corrosion 

Metal + atmosphere substance โ†’ Undesirable substance 

Ex: 

โ˜… Rusting of iron 

โ˜… Copper + Carbon dioxide โ†’ Copper carbonate 

Copper loses its brown surface and gain green coat (copper carbonate)

โ˜… Silver + Sulfur โ†’Silver sulphide 

Silver article become black (silver sulphide)

โ†’ Prevention of Corrosion 

โ˜…Painting, 

โ˜…Oiling, 

โ˜… Greasing, 

โ˜… Galvanising, chrome plating, 

โ˜…Anodising 

โ˜… Making alloys

Galvanising: coating zinc on iron to prevent rust.

โ†’Alloys:

Homogeneous mixer of two or more metals is called alloy.

Ex:

โ˜… Brass : Copper and Zinc

โ˜… Bronze : Copper and Tin

โ˜… Solder : Lead and Tin

         ๐—–๐—ฎ๐—ฟ๐—ฏ๐—ผ๐—ป ๐—”๐—ป๐—ฑ ๐—œ๐˜๐˜€ ๐—–๐—ผ๐—บ๐—ฝ๐—ผ๐˜‚๐—ป๐—ฑ๐˜€       

โ†’ Covalent bond: 

Sharing of electrons between two atoms.

โ†’ Ionic Bond:

Transfer of electrons from one atom to other.

โ†’ Catenation:

Carbon can able to form bond with other carbon atom give large molecules.

โ†’ Tetravalency: 

Carbon has 4 valency. It can bond with other carbon atoms or other than carbon atom.

โ†’ Carbon cannot form C4+ cation 

Because of removal of 4 elections from a carbon atom would require a large amount of energy.

โ†’ Carbon cannot form C4- anion 

Because it is difficult for the nucleus with 6 protons to hold 10 electrons.

โ†’ Saturated hydrocarbons:

โ˜… Single bond between two atoms.

โ˜… Less reactive 

โ˜… Give clean flame 

โ˜… Ex: Alkanes (methane, Ethane, Propane..)

โ†’ Unsaturated hydrocarbons:

โ˜… Double / Triple bond between carbon atoms.

โ˜… More reactive 

โ˜… Give yellow flame 

โ˜… Ex: Alkenes and Alkynes 

โ†’ Functional groups 

Atoms / group of atoms which given specific properties to carbon compounds.

Ex:

โ˜… Alcohol: - OH

โ˜… Aldehydes :     -CHO

โ˜… Ketone :    C=O

โ˜… Carboxylic acid:  -COOH

โ†’ Structural isomers:

Same molecular formula but different structures are called structural isomers.

Structural isomers of butane:



โ†’ Hydrogenation / Addition Reaction 

Conversion of unsaturated oils into saturated fats by adding hydrogen in the presence of  nickel catalyst.
Or
                                      H2
Unsaturated oil        โ†’     Saturated fat
                                 Ni

โ†’ Substitution reaction:

Reaction in which hydrogen atoms of a hydrocarbon are replaced by other atoms. 

Ex: CH4 + Cl2 โ†’ CH3Cl + HCl.

โ†’ Combustion reaction:

Burning of carbon or carbon-containing compounds in the presence of air or oxygen to produce carbon dioxide, heat and light

2CH3OH + 3O2 โ†’ 4H2O + 2CO2

โ†’ Esterification: 

Acid + alcohol โ†’ esters.

Ester is Used to make perfumes and as flavouring agents.

โ†’ Saponification : 

Alkaline base +  long chain carboxylic acid โ†’ soaps 

โ†’Cleaning action of soap.

โ˜… The ionic end of soap interacts with water while the carbon chain interacts with oil and form micelles.

โ˜… The soap micelles pulling out the dirt from cloth.

โ†’ Soaps and Detergents






























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