Fundamental Concepts of Chemistry

Fundamental Concepts of Chemistry

• Matter: Anything that has mass and occupies space. Exists in solid, liquid, and gas states.

• Atoms: Basic unit of matter, composed of protons, neutrons, and electrons.

  • Protons: Positive charge, located in the nucleus.
  • Neutrons: No charge, located in the nucleus.
  • Electrons: Negative charge, orbiting the nucleus.

• Elements: Pure substances made up of only one type of atom; represented by symbols on the periodic table.

The Periodic Table

• Organizes elements by increasing atomic number.
• Groups (columns) indicate elements with similar chemical properties.
• Periods (rows) indicate energy levels of electrons.

Chemical Bonds

• Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions.
• Covalent Bonds: Formed when atoms share electrons.
• Metallic Bonds: Involves a 'sea of electrons' freely moving among metal atoms.

Chemical Reactions

• Reactants: Substances that undergo a change in a reaction.
• Products: Substances formed as a result of a reaction.
• Types of Reactions:
  • Synthesis: A + B → AB
  • Decomposition: AB → A + B
  • Single Replacement: A + BC → AC + B
  • Double Replacement: AB + CD → AD + CB
  • Combustion: Hydrocarbon + O₂ → CO₂ + H₂O

Acids and Bases

• Acids: Substances that release hydrogen ions (H⁺) in solution (e.g., HCl).
• Bases: Substances that release hydroxide ions (OH⁻) in solution (e.g., NaOH).
• pH Scale: Measures acidity (pH < 7) and alkalinity (pH > 7); neutral at pH 7.

Stoichiometry

• Involves calculations related to the quantities of reactants and products in a chemical reaction.
• Based on the conservation of mass: mass of reactants = mass of products.

Thermochemistry

• Studies the heat changes associated with chemical reactions.
• Exothermic Reactions: Release heat.
• Endothermic Reactions: Absorb heat.

States of Matter

• Solid: Definite shape and volume.
• Liquid: Definite volume, takes the shape of the container.
• Gas: No definite shape or volume, expands to fill the container.

Solutions

• Solvent: Substance that dissolves the solute (e.g., water).
• Solute: Substance that is dissolved (e.g., salt).
• Concentration: Amount of solute in a given volume of solvent.

Key Laboratory Techniques

• Titration: Technique to determine concentration by reacting a solution with a known concentration.
• Filtration: Separating solids from liquids using a filter.
• Distillation: Separating mixtures based on differences in boiling points.

Safety in the Chemistry Lab

• Always wear safety goggles and gloves.
• Know the location of safety equipment (eyewash, fire extinguisher).
• Properly label and store chemicals.

Fundamental Concepts of Chemistry

• Matter has mass and occupies space, existing in solid, liquid, and gas states.
• Atoms are the fundamental units of matter, consisting of protons, neutrons, and electrons.
• Protons possess a positive charge and are found in the nucleus.
• Neutrons carry no charge and reside in the nucleus.
• Electrons are negatively charged particles that orbit around the nucleus.
• Elements are pure substances made of only one type of atom, represented by symbols on the periodic table.

The Periodic Table

• Elements are organized by increasing atomic number.
• Groups (columns) signify elements with similar chemical properties.
• Periods (rows) indicate the number of energy levels occupied by electrons in the atoms.

Chemical Bonds

• Ionic bonds result from the transfer of electrons between atoms, forming charged ions.
• Covalent bonds are created when pairs of electrons are shared between atoms.
• Metallic bonds involve a collective pool of electrons that move freely among metal atoms.

Chemical Reactions

• Reactants are the initial substances that undergo transformation during a reaction.
• Products are the new substances formed as a result of the chemical reaction.
• Types of chemical reactions include:
  • Synthesis: Two or more reactants combine to form one product (A + B → AB).
  • Decomposition: A single compound breaks down into two or more products (AB → A + B).
  • Single Replacement: One element replaces another in a compound (A + BC → AC + B).
  • Double Replacement: Exchange of ions between two compounds (AB + CD → AD + CB).
  • Combustion: A hydrocarbon reacts with oxygen to produce carbon dioxide and water (Hydrocarbon + O₂ → CO₂ + H₂O).

Acids and Bases

• Acids are substances that release hydrogen ions (H⁺) in solution, like hydrochloric acid (HCl).
• Bases release hydroxide ions (OH⁻) in solution, such as sodium hydroxide (NaOH).
• The pH scale measures acidity (pH < 7) and alkalinity (pH > 7), with neutrality at pH 7.

Stoichiometry

• Stoichiometry involves calculations regarding reactant and product quantities in chemical reactions.
• It is based on the principle of conservation of mass, where the mass of reactants equals the mass of products.

Thermochemistry

• Thermochemistry examines the heat changes that occur during chemical reactions.
• Exothermic reactions release heat, while endothermic reactions absorb heat.

States of Matter

• Solids have a definite shape and volume.
• Liquids have a definite volume but take the shape of their containers.
• Gases have no fixed shape or volume, expanding to fill their containers.

Solutions

• Solvents dissolve solutes; for example, water acts as a solvent for salt.
• Solutes are substances that are dissolved within the solvent.
• Concentration refers to the quantity of solute contained in a specific volume of solvent.

Key Laboratory Techniques

• Titration measures concentration through the reaction of a solution with a known concentration.
• Filtration is used to separate solids from liquids using a filtering medium.
• Distillation separates liquid mixtures based on differences in boiling points.

Safety in the Chemistry Lab

• Safety goggles and gloves should always be worn to protect against hazards.
• Familiarity with the location of safety equipment (eyewash stations, fire extinguishers) is crucial.
• Chemicals must be properly labeled and stored to prevent accidents.