Chemical Reactions

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In chemistry, a chemical reaction is a process which leads to the transformation of one set of chemical substances to another.


Writing Balanced Chemical Equations

All balanced chemical equations have the following features:- mass must be conserved- same number and types of atoms on both sides of the equation- formula subscripts must not be changed- final balanced equation can contain whole number or fraction coefficients

The Law of Conservation of Mass

 MASS IS NEITHER CREATED NOR DESTROYED IN ANY ORDINARY CHEMICAL REACTION BECAUSE ATOMS ARE NOT CREATED NOR DESTROYED IN ANY ORDINARY CHEMICAL REACTION                     

Formation or Single Replacement

element +element --> Compound


Single Decomposition

Compound--> element + element


Single Decomposition

Compound--> element + element

Single Replacement

Element + compound --> element + compound

Cu (s) + 2 AgNO3 (aq) --> 2 Ag (s) + Cu(NO3)2 (aq)

Double Replacement

Compound + compound --> compound + compound

2 NaI (aq) + Pb (NO3)2 (aq) --> PbI2 (s) + 2NaNO3 (aq)

Combustion

compound + O2 (g) --> most common oxides of elements of the compound

Note: most of the time your combustion reaction will be hydrocarbon combustions (involving compounds of the formula CxHy). The format now becomes hydrocarbon + oxygen --> carbon dioxide + water vapour

C3H8 (g) + 5 O2 --> 3CO2 (g) + 4 H2O (g)



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