Class notes Chemistry Chemistry

A list of important chemistry reactions

1. General Inorganic Reactions
a) Combination Reactions

Two or more substances combine to form a single product.
Example:

2Mg+O2→2MgO2Mg + O_2 \rightarrow 2MgO


b) Decomposition Reactions

A single compound breaks down into two or more simpler products.
Examples:

 Thermal decomposition of CaCO₃:

CaCO3→ΔCaO+CO2CaCO_3 \xrightarrow{\Delta} CaO + CO_2

 Electrolysis of water:

2H2O→electricity2H2+O22H_2O \xrightarrow{electricity} 2H_2 + O_2



c) Displacement Reactions

A more reactive element displaces a less reactive element from its compound.
Example:

Zn+CuSO4→ZnSO4+CuZn + CuSO_4 \rightarrow ZnSO_4 + Cu


d) Double Displacement / Precipitation Reaction

Two compounds react to form two new compounds.
Example:

AgNO3+NaCl→AgCl↓+NaNO3AgNO_3 + NaCl \rightarrow AgCl \downarrow + NaNO_3

, 2. Organic Chemistry Reactions
a) Substitution Reaction (Alkanes)

Alkanes react with halogens in presence of light or heat.
Example:

CH4+Cl2→hvCH3Cl+HClCH_4 + Cl_2 \xrightarrow{hv} CH_3Cl + HCl


b) Addition Reaction (Alkenes and Alkynes)

Unsaturated hydrocarbons add halogens, hydrogen, or halogen acids.

 Hydrogenation:

CH2=CH2+H2→Ni/PtCH3−CH3CH_2=CH_2 + H_2 \xrightarrow{Ni/Pt} CH_3-CH_3

 Halogenation:

CH2=CH2+Br2→CH2Br−CH2BrCH_2=CH_2 + Br_2 \rightarrow CH_2Br-CH_2Br

 Hydrohalogenation:

CH2=CH2+HBr→CH3−CH2BrCH_2=CH_2 + HBr \rightarrow CH_3-CH_2Br



c) Elimination Reaction

Haloalkanes form alkenes by loss of a small molecule.
Example:

CH3CH2Br+KOH(alc)→ΔCH2=CH2+HBrCH_3CH_2Br + KOH(alc) \xrightarrow{\Delta}
CH_2=CH_2 + HBr


d) Oxidation Reactions

 Alcohol to aldehyde or acid:

CH3CH2OH→[O]CH3CHO→[O]CH3COOHCH_3CH_2OH \xrightarrow{[O]}
CH_3CHO \xrightarrow{[O]} CH_3COOH

 Combustion of hydrocarbons: