Chemical Equations and Reactions

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By: rajnegi (17 month(s) ago)

yur ppt is very nice

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Chemical Equations and Reactions : 

Chemical Equations and Reactions Chapter 8

Objectives for today : 

Objectives for today List three observations that suggest a chemical reaction has occurred List three requirements for correctly written chemical equations Write word equations Balance a formula equation by inspection Classify chemical reactions

Indications of a chemical reaction : 

Indications of a chemical reaction Evolution of heat and light Production of a gas Formation of a precipitate Color change

Characteristics of a Chemical Equation : 

Characteristics of a Chemical Equation The equation must represent all the known facts The equations must contain the correct formulas for the reactants and products The law of conservation of mass must be satisfied

Types of Reactions : 

Types of Reactions Synthesis Decomposition Single replacement Double replacement Combustion

Synthesis : 

Synthesis Synthesis reaction also know as composition A + X  AX 2Mg + O2  2MgO

Decomposition : 

Decomposition Decomposition –one compound undergoes a reaction that produces two or more simpler substance AX  A + X 2H20  2H2 + O2

Single replacement reaction : 

Single replacement reaction one element replaces a similar element in a compound A + BX AX + B Y + BX  BY + X Mg + 2HCl  H2 + MgCl2

Double Replacement reaction : 

Double Replacement reaction the ions of two compounds exchange places in an aqueous solution to form two new compounds a. AX + BY  AY + BX b. 2KI + Pb(NO3)2  PbI2 +2KNO3

Combustion : 

Combustion a substance combines with oxygen releasing a large amount of energy in the form of light and heat burning of propane C3H8 + 5O2  3CO2 + 4H2O