Basic Concepts of Chemistry

Basic Concepts of Chemistry

• Atoms: The basic unit of matter, consisting of protons, neutrons, and electrons.
• Molecules: Two or more atoms bonded together.
• Elements: Pure substances made of one type of atom, listed in the periodic table.
• Compounds: Substances formed when two or more different atoms chemically bond.

States of Matter

• Solid: Definite shape and volume; particles tightly packed.
• Liquid: Definite volume but takes the shape of the container; particles are close but can move.
• Gas: No definite shape or volume; particles are far apart and move freely.
• Plasma: Ionized gas with free electrons; found in stars and lightning.

Chemical Bonding

• Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in charged ions.
• Covalent Bonds: Involves the sharing of electron pairs between atoms.
• Metallic Bonds: Occurs between metal atoms, involving a 'sea' of delocalized electrons.

Chemical Reactions

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

Stoichiometry

• Mole: A quantity that represents 6.022 x 10²³ particles (Avogadro's number).
• Molar Mass: The mass of one mole of a substance, usually expressed in grams/mole.
• Balancing Equations: Ensures the same number of each type of atom on both sides of a chemical equation.

Acids and Bases

• Acids: Substances that donate protons (H⁺ ions); they have a pH less than 7.
• Bases: Substances that accept protons; they have a pH greater than 7.
• pH Scale: Ranges from 0 to 14, measuring the acidity or basicity of a solution.

Thermodynamics in Chemistry

• Exothermic Reactions: Release heat, temperature increases.
• Endothermic Reactions: Absorb heat, temperature decreases.
• Enthalpy (ΔH): The total heat content in a system; changes during reactions.

Laboratory Safety

• Personal Protective Equipment (PPE): Goggles, gloves, lab coats.
• Proper Labeling: All chemicals must be clearly labeled with contents and hazards.
• Emergency Procedures: Know locations of safety showers, eyewash stations, and fire extinguishers.

Periodic Table Trends

• Atomic Radius: Increases down a group; decreases across a period.
• Ionization Energy: Energy required to remove an electron; increases across a period; decreases down a group.
• Electronegativity: Ability of an atom to attract electrons; increases across a period; decreases down a group.

Types of Solutions

• Solvent: The substance that dissolves the solute.
• Solute: The substance being dissolved.
• Concentration: The amount of solute present in a given volume of solution.

These notes encompass essential concepts in chemistry, offering a structured overview suitable for study and reference.

Basic Concepts of Chemistry

• Atoms are the foundational units of matter composed of protons, neutrons, and electrons.
• Molecules form when two or more atoms bond together.
• Elements are pure substances consisting of a single type of atom and are organized on the periodic table.
• Compounds are formed when two or more different types of atoms chemically bond.

States of Matter

• Solids have a definite shape and volume due to their tightly packed particles.
• Liquids have a definite volume but take the shape of their container because their particles are close together but can move.
• Gases lack a definite shape or volume; particles are far apart and move freely.
• Plasma is an ionized gas with free electrons, commonly found in stars and lightning.

Chemical Bonding

• Ionic bonds occur when electrons are transferred from one atom to another, resulting in charged ions.
• Covalent bonds involve the sharing of electron pairs between atoms.
• Metallic bonds occur between metal atoms, featuring a 'sea' of delocalized electrons.

Chemical Reactions

• Reactants are substances that undergo a chemical change.
• Products are substances created as a result of a chemical reaction.
• Types of Reactions:
  • Synthesis involves two or more reactants combining to form a product.
  • Decomposition is the breakdown of a single compound into simpler substances.
  • Single Replacement occurs when one element replaces another in a compound.
  • Double Replacement involves the exchange of ions between two compounds.

Stoichiometry

• Mole represents 6.022 x 10²³ particles (Avogadro's number), a fundamental unit of measurement in chemistry.
• Molar mass is the mass of one mole of a substance, typically expressed in grams/mole.
• Balancing equations ensures the same number of each type of atom appears on both sides of a chemical equation.

Acids and Bases

• Acids are substances that donate protons (H⁺ ions), resulting in a pH less than 7.
• Bases are substances that accept protons, resulting in a pH greater than 7.
• pH scale ranges from 0 to 14, measuring the acidity or basicity of a solution.

Thermodynamics in Chemistry

• Exothermic reactions release heat, causing a temperature increase.
• Endothermic reactions absorb heat, leading to a temperature decrease.
• Enthalpy (ΔH) represents the total heat content in a system, which can change during reactions.

Laboratory Safety

• Personal Protective Equipment (PPE) includes goggles, gloves, and lab coats.
• Proper labeling is crucial to prevent accidents, with chemicals clearly labeled with contents and hazards.
• Emergency Procedures require knowledge of the location of safety showers, eyewash stations, and fire extinguishers.

Periodic Table Trends

• Atomic radius increases down a group and decreases across a period.
• Ionization energy represents the energy needed to remove an electron; it increases across a period and decreases down a group.
• Electronegativity reflects an atom's ability to attract electrons; it increases across a period and decreases down a group.

Types of Solutions

• Solvent is the substance that dissolves the solute.
• Solute is the substance being dissolved.
• Concentration quantifies the amount of solute present in a given volume of solution.