Basic Concepts of Chemistry

Atoms: Fundamental building blocks of matter; consist of protons, neutrons, and electrons.
Elements: Pure substances made of one type of atom; listed in the periodic table.
Compounds: Substances formed by chemically combining two or more elements in fixed ratios.

Solid: Definite shape and volume; particles are tightly packed.
Liquid: Definite volume but no definite shape; particles are close but can move past one another.
Gas: No definite shape or volume; particles are far apart and move freely.
Plasma: Ionized gas with free electrons; found in stars, including the sun.

Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions.
Covalent Bonds: Formed when atoms share electrons to achieve stability.
Metallic Bonds: Occur between metal atoms, where electrons are shared over a lattice of atoms.

Reactants: Substances that undergo a chemical change.
Products: New substances formed as a result of a chemical reaction.
Types of Reactions:
- Synthesis: Two or more reactants combine to form a single product.
- Decomposition: A single compound breaks down into two or more products.
- Single Replacement: An element replaces another in a compound.
- Double Replacement: The exchange of ions between two compounds.

Acids: Substances that release hydrogen ions (H+) in solution; have a pH less than 7.
Bases: Substances that release hydroxide ions (OH-) in solution; have a pH greater than 7.
pH Scale: Measures the acidity or alkalinity of a solution on a scale of 0 to 14.

Groups: Vertical columns; elements in the same group share similar chemical properties.
Periods: Horizontal rows; represent increasing energy levels of electrons.
Metals, Nonmetals, and Metalloids: Distinct categories based on physical and chemical properties.

Mole: Basic unit of amount in chemistry (6.022 x 10²³ particles).
Molar Mass: Mass of one mole of a substance, calculated from atomic masses.
Balanced Equations: Represent the conservation of mass; number of atoms for each element is the same on both sides.

Hydrocarbons: Compounds made only of carbon and hydrogen.
Functional Groups: Specific groups of atoms within molecules that determine characteristic chemical reactions.
Isomers: Compounds with the same molecular formula but different structural arrangements.

Macromolecules: Large molecules essential for life; include proteins, nucleic acids, carbohydrates, and lipids.
Enzymes: Biological catalysts that speed up chemical reactions in cells.

Titration: Method to determine concentration of a solution by reacting it with a solution of known concentration.
Chromatography: Technique for separating mixtures based on differences in partitioning behavior.
Spectroscopy: Method for analyzing the interaction of light with matter to determine composition.

Atoms consist of protons (positively charged), neutrons (neutral), and electrons (negatively charged), forming the basic units of matter.
Elements are pure substances made up of only one type of atom, categorized in the periodic table based on their properties.
Compounds are formed when two or more elements chemically combine in fixed ratios, resulting in new substances with distinct characteristics.

Solids have a fixed shape and volume because their particles are closely packed together, allowing only limited movement.
Liquids maintain a definite volume but not a definite shape, with particles that are close together yet can move freely past one another.
Gases have neither a definite shape nor volume; their particles are spaced far apart, moving freely and filling their container entirely.
Plasma is an ionized state of matter containing free electrons, commonly found in stars and including the sun.

Ionic bonds occur through the transfer of electrons from one atom to another, generating charged ions that attract each other.
Covalent bonds form when atoms share electrons, enabling them to achieve stable electron configurations.
Metallic bonds involve a lattice of metal atoms where electrons are shared collectively, allowing conductivity and malleability.

Reactants are the initial substances that participate in a chemical reaction, while products are the new substances formed.
Synthesis reactions combine multiple reactants into a single product, whereas decomposition reactions break down a compound into multiple products.
Single replacement reactions involve one element substituting another in a compound, while double replacement reactions entail the exchange of ions between two compounds.

Acids produce hydrogen ions (H+) in solution and typically have a pH lower than 7, indicating increased acidity.
Bases generate hydroxide ions (OH-) in solution and usually have a pH greater than 7, indicating increased alkalinity.
The pH scale ranges from 0 to 14, with 7 being neutral; values below 7 indicate acidic solutions, while values above indicate basic solutions.

Groups are vertical columns in the periodic table where elements share similar chemical properties, reflecting their valence electron configuration.
Periods are horizontal rows that indicate the increasing energy levels of electrons as one moves from left to right across the table.
Metals, nonmetals, and metalloids are distinct categories of elements based on their physical and chemical properties, influencing their reactivity and applications.

Endothermic reactions absorb heat, leading to a temperature decrease in the surroundings, often resulting in bonds being broken.
Exothermic reactions release heat, causing a temperature increase, often associated with the formation of new bonds.
Enthalpy (ΔH) is the measure of total heat content in a system, crucial for understanding energy changes during reactions.

The mole is a fundamental unit of measurement in chemistry, representing 6.022 x 10²³ particles, and is essential for quantifying substances in reactions.
Molar mass is the mass of one mole of a substance, derived from the sum of the atomic masses of its constituent atoms.
Balanced equations express the conservation of mass, with an equal number of atoms for each element on both sides of the equation, ensuring accuracy in chemical calculations.

Hydrocarbons are organic compounds composed solely of carbon and hydrogen, forming the backbone of various organic molecules.
Functional groups are specific collections of atoms attached to hydrocarbon chains that influence the chemical behavior and reactivity of compounds.
Isomers are compounds with identical molecular formulas but differing in structural arrangements, leading to variations in physical and chemical properties.

Macromolecules, including proteins, nucleic acids, carbohydrates, and lipids, play vital roles in biological functions and structures.
Enzymes act as biological catalysts, significantly accelerating chemical reactions within cells and facilitating metabolic processes.

Titration is a quantitative analytical method used to determine the concentration of a solution by reacting it with a solution of known concentration.
Chromatography separates mixtures based on the different distribution of components between stationary and mobile phases, allowing for analysis and purification.
Spectroscopy analyzes the interaction of light with matter, revealing information about composition and concentration based on absorbed or emitted light.