Inorganic Compounds and Their Classification

Study Notes

Inorganic compounds are chemical compounds that do not contain carbon-hydrogen bonds. This broad definition excludes most organic molecules.
Exceptions to the rule include simple carbon compounds like carbon dioxide (CO2), carbon monoxide (CO), carbonates, cyanides, and carbides.
Inorganic compounds may contain carbon, but they are not considered organic due to their structures.
Classification is based on the nature of the constituent elements and the types of bonds involved. Examples of classifications are oxides (compounds with oxygen), halides (compounds with halogens), sulfides (compounds with sulfur), and salts.

Melting and Boiling Points: Vary widely with structure. Some are volatile, some are solids at room temperature (e.g., metals, salts) while others are gases (e.g., some oxides). High melting and boiling points often indicate ionic bonding.
Solubility: Ranges from highly soluble in water (e.g., ionic compounds) to practically insoluble. Solubility depends on factors like polarity and ion-dipole interactions.
Conductivity: Many ionic compounds conduct electricity in molten or aqueous solutions because ions are free to move. Certain metals, like copper, are good conductors in solid state.
Chemical Reactivity: Inorganic compounds exhibit a wide range of reactivity. Some, like acids and bases, react vigorously with other substances. Others are more inert. Many undergo redox reactions.

Acids: Examples include hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), and carbonic acid (H2CO3).
Bases: Examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2).
Salts: Examples are sodium chloride (NaCl), potassium nitrate (KNO3), and calcium sulfate (CaSO4).
Metals: Iron (Fe), Copper (Cu), Aluminum (Al), and Zinc (Zn)
Non-metals: Sulfur (S), Oxygen (O2), Nitrogen (N2)

Fertilizers: Ammonium nitrate (NH4NO3), potassium phosphate (K3PO4), and urea are important inorganic fertilizers.
Building materials: Cement and concrete are composed of inorganic compounds like calcium silicates and calcium aluminates.
Catalysis: Many inorganic compounds act as catalysts in industrial processes, speeding up reactions without being consumed. Platinum, palladium are examples
Pigments: Inorganic compounds produce a wide array of colours, widely utilized in paints, plastics, and coatings.
Water treatment: Chemicals like chlorine and alum are critical for purifying water.

Direct combination: Simple reactions where elements combine to form compounds (e.g., combining iron and sulfur to yield iron sulfide).
Decomposition reactions: Heating or applying other means breaks down compounds into simpler substances (e.g., decomposition of calcium carbonate into calcium oxide and carbon dioxide).
Displacement reactions: A more reactive element displaces a less reactive element from a compound (e.g., copper reacting with silver nitrate to form copper nitrate and silver).
Acid-base reactions: Reactions between acids and bases creating salts and water.
Precipitation reactions: Involves the formation of an insoluble solid when two solutions are combined.
Electrolysis: Using an electric current to drive a non-spontaneous reaction. Examples include the production of aluminum from aluminum ore.
Metathesis reactions: The exchange of ions between two ionic compounds yielding new ionic compounds.
High-temperature synthesis: Reactions are performed at exceptionally high temperatures to overcome activation barriers (making use of furnaces to achieve high temperatures)

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