Chemistry - Chemical Reactions (Types of Reactions, Oxides)

A Chemical Reaction is a process in which one or more substances (reactants) undergo a chemical change to form new substances (products) with different properties.

Direct Combination (Synthesis): Two or more elements or compounds combine to form a single product. General form: $A + B \rightarrow AB$. Example: $2Mg + O_2 \rightarrow 2MgO$.

Decomposition Reaction: A single compound breaks down into two or more simpler substances. Types include Thermal (using heat, e.g., $CaCO_3 \xrightarrow{\Delta} CaO + CO_2$), Electrolytic (using electricity), and Photochemical (using light).

Displacement Reaction: A more reactive element displaces a less reactive element from its salt solution. Example: $Fe + CuSO_4 \rightarrow FeSO_4 + Cu$.

Double Displacement Reaction: Two compounds react by an exchange of ions to form two new compounds. It includes Precipitation (formation of an insoluble solid) and Neutralization ($Acid + Base \rightarrow Salt + Water$).

Oxides: Binary compounds formed by the reaction of oxygen with other elements. They are classified based on their chemical nature.

Basic Oxides: Usually metallic oxides that react with water to form bases or react with acids to form salt and water. Example: $Na_2O$, $CaO$.

Acidic Oxides: Usually non-metallic oxides that react with water to form acids. Example: $SO_2$, $CO_2$, $P_2O_5$.

Amphoteric Oxides: Metallic oxides that show both acidic and basic properties; they react with both acids and bases to form salt and water. Example: $ZnO$, $Al_2O_3$.

Neutral Oxides: Oxides that show neither acidic nor basic properties and do not react with acids or bases. Example: $CO$, $NO$, $N_2O$, $H_2O$.