Chemistry Unit 3

Matter

  1. Definition: Matter is anything in the Universe that has mass and takes up space.

  2. States of Matter:

    • Solid: Has a definite shape and volume.

    • Liquid: Has a definite volume but takes the shape of its container.

    • Gas: Has no definite shape or volume.

    • Plasma: An ionized gas.

Classifying Matter

  1. Mixtures: Combinations of substances that are physically mixed but not chemically combined.

    • Homogeneous Mixtures: Have uniform composition throughout (e.g., saltwater).

    • Heterogeneous Mixtures: Have non-uniform composition (e.g., salad).

  2. Pure Substances: Have a fixed composition and distinct properties.

    • Elements: Cannot be broken down into simpler substances (e.g., gold, oxygen).

    • Compounds: Consist of two or more elements chemically combined in a fixed ratio (e.g., water H_2O).

Solutions and Separating Mixtures

  1. Solutions: Homogeneous mixtures where one substance (the solute) is dissolved in another (the solvent).

  2. Separating Mixtures: Physical processes used to separate mixtures into their components.

    • Filtration: Separates solids from liquids using a filter.

    • Distillation: Separates liquids with different boiling points.

    • Evaporation: Separates a soluble solid from a liquid by evaporating the liquid.

    • Magnetism: Uses a magnet to separate magnetic substances from non-magnetic ones.

Energy

  1. Definition: The ability to do work.

  2. Forms of Energy:

    • Kinetic Energy: The energy of motion. KE = \frac{1}{2}mv^2

    • Potential Energy: Stored energy. PE = mgh

    • Thermal Energy: Heat energy.

    • Chemical Energy: Energy stored in chemical bonds.

    • Electrical Energy: Energy of moving electric charges.

    • Radiant Energy: Electromagnetic radiation (e.g., light).

  3. Law of Conservation of Energy: Energy cannot be created or destroyed; it can only be converted from one form to another.

Properties and Mass Changes

  1. Physical Properties: Characteristics that can be observed or measured without changing the substance's composition (e.g., color, density, melting point).

  2. Chemical Properties: Describe how a substance changes into a new substance through chemical reactions (e.g., flammability, reactivity).

  3. Mass Changes: The mass of a substance can change during physical and chemical processes. In chemical reactions, mass