Introduction to Basic Chemistry Concepts

Introduction to Chemistry

• Chemistry is the study of matter, its properties, changes, and the energy associated with those changes.
• Matter is defined as anything with mass that occupies space.

Fundamental Definitions

• Matter: Physical material of the universe.
• Property: Characteristic that distinguishes a type of matter.
• Atoms: Tiny building blocks of matter.
• Molecules: Combinations of two or more atoms in specific shapes.
• Substance: Matter with a definite composition and distinct properties.

Classification of Matter

• Element: Cannot be separated into simpler substances by chemical means.
• Compound: Made of atoms from two or more elements, chemically united in fixed proportions.
• Mixture: A combination of two or more substances where each retains its identity. Mixtures can be homogeneous or heterogeneous.
• Homogeneous Mixture: Uniform composition throughout; also called a solution.
• Heterogeneous Mixture: Non-uniform composition.

Properties of Matter

• Physical Properties: Observable without changing the substance (e.g., color, odor, density, boiling point).
• Chemical Properties: Describe how substances may change or react (e.g., flammability).
• Intensive Properties: Do not depend on the amount of substance (e.g., temperature, melting point).
• Extensive Properties: Depend on the amount of substance (e.g., mass, volume).

Changes of Matter

• Physical Change: Changes appearance without altering composition (e.g., state changes).
• Chemical Change: Transforms substance into a different one, known as a chemical reaction (e.g., burning hydrogen).

Basic Concepts of Energy

• Energy is defined as the ability to do work, existing in potential and kinetic forms.
• Potential Energy: Energy due to the position of an object.
• Kinetic Energy: Energy due to the motion of an object.
• The total energy of an object is the sum of its potential and kinetic energy.
• Lower energy states are more stable and favored.
• Energy is conserved and can be converted from one form to another, never created or destroyed.