Chapter 7_1and 2_3_Foundations of Chemistry_States of Matter (2)

Be able to:
- Describe matter, atoms, substances, and compounds with examples.
- Distinguish between types of mixtures, explain differences, and provide examples.
- Differentiate states of matter, physical and chemical changes, and outline physical properties of matter.

Matter: Anything that has mass and occupies space.
- Atom: Smallest particle and the fundamental building block of matter.

Structure: Composed of three subatomic particles:
- Proton: Positively charged particle.
- Neutron: No charge (neutral particle).
- Electron: Negatively charged particle.
Nucleus: Center of the atom containing protons and neutrons.

Substance: Matter with a uniform composition.
- Element: Contains only one type of atom.
- Compound: Consists of two or more different elements chemically bonded together.
- Chemical formula: A representation of a compound using symbols and numbers.
- Symbols show different elements and subscripts show quantity.
- Properties of compounds differ from those of their constituent elements.

Mixture: Matter that combines physically and can be separated by physical means (e.g., black pepper and sugar).
- Heterogeneous mixture: Not evenly mixed (e.g., salad).
- Homogeneous mixture: Evenly mixed (e.g., saltwater).

Compounds: Components are chemically bonded.
Solutions: Components are physically mixed.
- Solute: The substance in the least amount.
- Solvent: The substance in the greatest amount (usually a liquid).

Physical Property: Characteristic observable or measurable without changing the substance's identity.
- State of matter: Solid, liquid, gas, dependent on temperature (72°F / 21°C).
- Mass: Size-dependent; measures the amount of matter.
- Volume: Amount of space occupied, measured in cubic centimeters (cm³) or milliliters (mL).
- Melting Point: Temperature at which a solid becomes a liquid.
- Boiling Point: Temperature at which a liquid becomes a gas.
- Density: Ratio of mass to volume (D = M/V).
- Electrical Conductivity: Ability to conduct electricity (conductors vs. insulators).
- Solubility: Ability of a substance to dissolve in another.
Parts of a mixture can be separated by physical means (e.g., boiling saltwater).

Identity Preservation: The matter retains its identity through size, shape, or state changes.
- Example: Chewing food changes shape but not identity.
Matter changes state with thermal energy changes:
- Solid to Liquid: Added thermal energy loosens bonds.
- Liquid to Gas: Further added thermal energy.
- Sublimation: Solid to gas (skipping liquid state).
- Condensation: Gas to liquid (thermal energy removed).
- Freezing: Liquid to solid (thermal energy removed).
- Deposition: Gas to solid.
- Dissolving: A physical change.
Reversible Changes: Solid to liquid and back.
Irreversible Changes: E.g., cutting cloth.