CBSE CLASS-10 Chemistry Chapter-1 Chemical Reaction and Equation Notes
CHAPTER -1
Chemical Reaction and Equation Notes
Chemical Reaction
It is a process in which two or more substances interect to form a new substance having entirly new character.
The symbolic representation of chemical reaction is known as chemical eqution
The substance that take part in chemical reaction is known as reactant that formed after the chemical reaction is known as product.
◆ Characteristics of chemical reaction
1. Evolution of Gas
some chemical reaction is characterised by evolution of gas it may be occured in the form of bubble.
Hydrogen + Oxygen -----> Water H2 + O2 ----->H2O
2. Formation of precipitate
some chemical reaction is characterised by formation of insoluble product called precipatate.
Sodium + Hydrochloric acid ------> SodiumCloride + Hydrogen
Na + HCL -------> NaCl + H2
3. Change in color
some chemical reaction is characterised by change in color.
Copper Sulphate + Hydrogen Sulphide ------> Copper Sulphide + Sulphuric acid
CuSO4(aq) + H2S(g) -------> CuS(s) + H2SO4
4. Change in Temp
Some chemical reaction is characterised by change in temperature during some chemical reaction energy get librated in the form of heat such reaction is called exothermic reaction.
coal + Oxygen ------> Carbon dioxide + Heat + Light
C(s) + O2 -----> CO2 + Heat + Light
Those Chemical reaction in which heat is observed is called indothermic reaction.
limestone + Heat -----> Quicklime + Carbon dioxide
CaCO3(s) + Heat ------> CaO(s) + CO2(g)
5. Change in state
some chemical reaction is characteraised by change in state.
Hydrogen + Oxygen -----> water
H2 + O2 ----->H2O
SYMBOLS
(s) - Solid
(l) - liquid
(g) - Gas
(aq) - aquous solution
∆ - Heat
- Evolution of gas
- Formation of Precipitate
∆ - Heat
- Reversable rection
◆ Types of Chemical reaction
1. Combination Reaction
2. Decomposition Reaction
3. Displacement Reaction
4. Double Displacement Reaction
5. Oxidation Reaction
6. Reduction Reaction
1.Combination Reaction
In this chemical reaction two or more reactant combine together to form a single product.
CaO + CO2 -----> CaCO3
2. Decomposition Reaction
In this chemical reaction a single compound get splited into two or more product.
It is of three type :-
( i )Thermal Decomposition : The decomposition with the help of heat.
CaCO3 ------> CaO + CO2
( ii ) Electrical Decomposition : The decomposition done with help of electricity.
2H2O ------> 2H2 + O2
( iii ) Photolightic Decomposition : The decomposition done with the help of sunlight.
2AgCl -------> 2Ag + Cl2
3. Displacement Reaction
In this chemical reaction more reactive element displaces the less reactive element to form the its compound.
CuSO4 + Fe ------> FeSO4 + Cu
4. Dauble Displacement Reaction
In this chemistry reaction two ionic compound react with each other by exchanging there ions.
AgNO3 + NaCl ------> AgCl + NaNO3
5. Oxidation Reaction :
The addtion of oxygen or removal of hydrogen is called oxidation.
Mg + O2 -------> MgO
Mg is oxydised
6. Reduction Reaction :
The addtion of hydrogen or removal of oxugen is called reduction.
H2S + I2 -------> S + 2HI I2 is redused.
Effects of Oxidation
Oxidation is more useful as well as harmful for us burning of fuel ,respiration, are some useful effects of oxidation
The spoilish of an metal artical by the action of air moisture and chemical is known as corrosion
it reduces the mechanical strength as well as the siny surface of the metal due to this iron artical get covered with brown color flacky substance called rust and process said rusting.
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