Essential Principles of Chemistry: Laws, Concepts, and Reactions
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This document outlines fundamental laws, key concepts, and various types of chemical reactions crucial for understanding the principles of chemistry. Each point provides a concise definition, serving as a quick reference for core chemical knowledge.
Fundamental Chemical Laws and Concepts
Law of Conservation of Mass
Mass is neither created nor destroyed in a chemical reaction; it remains constant.
Law of Definite Proportions
A compound always contains the same elements in the same proportion by mass.
Law of Multiple Proportions
Elements combine in small, whole-number ratios to form different compounds.
Gay-Lussac's Law of Gaseous Volumes
The volumes of reacting gases (at constant temperature and pressure) are in simple whole-number ratios.
Newlands' Law of Octaves
Elements exhibit similar properties when arranged in groups of eight, with repeating patterns.
Ionization Enthalpy (First and Second)
Energy required to remove the first and second electrons from an atom, respectively.
Electron Gain Enthalpy
Energy released when an atom gains an electron.
Octet Rule
Atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight electrons.
Fajans' Rule
Predicts the formation of ionic or covalent bonds based on the size and charge of ions.
Features of Hybridization
Mixing atomic orbitals to form new, hybrid orbitals for bonding.
Molecular Orbital Theory
Describes electron distribution in molecules using molecular orbitals.
Standard Enthalpies (Reaction, Formation, Combustion, Atomization)
Measures heat changes in chemical processes.
Joule's Law of Constant Heat Summation
The heat change in a chemical reaction is constant regardless of the reaction path.
Lattice Enthalpy
Energy released or absorbed when ions in a gaseous state form a solid lattice.
Second and Third Laws of Thermodynamics
Describes entropy, spontaneity, and absolute zero temperature.
Characteristics of Equilibrium Constant
Indicates the extent of a chemical reaction at equilibrium.
Le Chatelier's Principle: Applications
Predicts how a system at equilibrium responds to changes in conditions.
Arrhenius Concept of Acids and Bases
Defines acids as substances that ionize in water to produce H⁺ ions.
Brønsted-Lowry Concept of Acids and Bases
Defines acids as proton (H⁺) donors and bases as proton acceptors.
Lewis Concept of Acids and Bases
Defines acids as electron pair acceptors and bases as electron pair donors.
Types of Chemical Reactions
Combination Reaction
Two or more substances combine to form a new substance.
Decomposition Reaction
A compound breaks down into simpler substances.
Displacement Reaction
One element displaces another from a compound.
Metal Displacement Reaction
A more reactive metal displaces a less reactive metal from its compound.
Non-Metal Displacement Reaction
A more reactive non-metal displaces a less reactive non-metal from a compound.
Disproportionation Reaction
An element in a compound undergoes both oxidation and reduction.
