Definition of Matter: Matter is anything that has mass and occupies volume. Key properties include mass (measured in grams) and volume (measured in L, dm3, mL, or cm3).

States of Matter: Matter exists as solids, liquids, or gases, each with distinct particle arrangements and properties.

Classification of Matter:

• Pure Substances: Have a fixed composition and distinct properties. They are either:

  • Elements: Contain only one type of atom. Can be monatomic (single atoms), diatomic (two atoms bonded), or polyatomic (several atoms bonded). Allotropes are different forms of the same element (e.g., O2 and O3 for oxygen).

  • Compounds: Contain two or more different types of atoms chemically bonded. Their properties differ from those of their constituent elements. Compounds can only be separated by chemical means. Example equations: C12H22O11(s)→12C(s)+11H2O(g) 2H2O(l)→2H2O(g)+O(g)

• Mixtures: Physical combinations of two or more substances. Not chemically bonded.

  • Homogeneous (solutions): Uniform composition throughout (e.g., air, alloys).

  • Heterogeneous: Non-uniform composition (e.g., sand in water, suspensions).

Separation of Mixtures: Mixtures can be separated by physical means such as sorting, filtration, magnetism, chromatography, density, and distillation.

Properties of Matter:

• Chemical Properties: Describe how a substance reacts with others (e.g., reactivity, flammability).

• Physical Properties: Can be observed without changing the substance (e.g., melting point, density).

• Extensive Properties: Depend on the amount of substance (e.g., mass, volume).

• Intensive Properties: Do not depend on the amount (e.g., density, boiling point).

Density: Defined as mass per unit volume. Density=massvolume Typical units: g/cm3 for solids, g/mL for liquids. Density is nearly constant for a given substance.

Physical and Chemical Changes:

• Physical Change: Alters form but not composition (e.g., melting, boiling).

• Chemical Change: Alters composition, forming new substances (e.g., combustion).

Energy in Chemical Changes:

• Law of Conservation of Energy: Energy is neither created nor destroyed in a chemical reaction.

• Endothermic: System absorbs heat (e.g., boiling water).

• Exothermic: System releases heat (e.g., freezing water).

The Mole Concept: Used to count atoms and molecules. 1 mole = 6.02 × 1023 particles (Avogadro's number). The mass of 1 mole of an element (in grams) equals its atomic mass from the periodic table.

Problem Solving with Moles:

• Conversions between grams, moles, and number of particles use the relationships: 1mol=6.02×1023particles

• Use dimensional analysis to solve for unknowns in chemical calculations.