States of Matter and Mixtures Quiz

States of Matter

• Solids: Definite shape and volume. Particles are closely packed, vibrating in place.
• Liquids: Definite volume, no definite shape. Particles are less tightly packed, taking the shape of their container.
• Gases: No definite shape or volume. Particles are spread out, moving freely.

Pure Substances

• Elements: Made of one type of atom. Examples: gold (Au), oxygen (O₂).
• Compounds: Made of two or more different atoms chemically bonded. Examples: water (H₂O), carbon dioxide (CO₂).

Mixtures

• Homogeneous mixtures: Uniform composition throughout. Examples: saltwater, air.
• Heterogeneous mixtures: Non-uniform composition. Examples: salad, sand.

Physical Properties

• Mass: Amount of matter, measured in grams or kilograms.
• Volume: Space occupied, measured in liters or cubic meters.
• Density: Mass per unit volume (mass/volume).
• Color, odor, taste: Sensory properties for identification.
• Melting/boiling points: Temperatures for phase changes (solid to liquid, liquid to gas).
• Hardness: Resistance to scratching or denting.
• Solubility: Ability to dissolve in another substance.

Chemical Properties

• Reactivity: How a substance interacts with others, causing chemical changes.
• Flammability: Ability to burn in the presence of oxygen.
• Acidity/basicity (pH): Measure of acidity; pH < 7 (acid), pH > 7 (base), pH = 7 (neutral).
• Oxidation state: Degree of oxidation of an atom in a compound.

Thermal Properties

• Thermal conductivity: Ability to conduct heat.
• Thermal expansion: Increase in volume with heating.

Electrical Properties

• Conductivity: Ability to conduct electricity.
• Resistivity: Resistance to electric current flow.

Atomic Structure

• Atomic number (Z): Number of protons in an atom (unique to each element).
• Number of protons: Equal to the atomic number (Z).
• Number of electrons: In a neutral atom, equals the number of protons.
• Number of neutrons (N): Calculated as Mass number (A) - Atomic number (Z).
• Mass number (A): Sum of protons and neutrons (A = Z + N).

Periodic Table

• Groups: Columns based on valence electrons.
  • Group 1 (Alkali metals): 1 valence electron (e.g., lithium, sodium).
  • Group 2 (Alkaline earth metals): 2 valence electrons (e.g., beryllium, magnesium).
  • Group 17 (Halogens): 7 valence electrons (e.g., fluorine, chlorine).
  • Group 18 (Noble gases): 8 valence electrons (e.g., helium, neon).
• Atomic radius: Decreases across a period, increases down a group.
• Ionization energy: Increases across a period, decreases down a group.
• Electronegativity: Increases across a period, decreases down a group.
• Metallic character: Decreases across a period, increases down a group.

Atom Structure (continued)

• Nucleus: Contains protons (positive) and neutrons (neutral).
• Electron cloud: Contains electrons (negative) orbiting the nucleus.
• Bohr-Rutherford diagrams: Used to show electron arrangement. First shell holds 2 electrons, second shell holds 8, etc. (third shell often simplified to 8).

Molecules & Compounds

• Molecules: Two or more atoms bonded together.
• Counting atoms: Use chemical formulas to determine atom numbers (e.g., H₂O = two hydrogen, one oxygen).
• Nomenclature:
  • -ide: For simple binary compounds (e.g., sodium chloride, NaCl).
  • -ate: For polyatomic ions with oxygen (e.g., sulfate, SO₄²⁻).
  • -ite: For polyatomic ions with less oxygen than the -ate ion (e.g., sulfite, SO₃²⁻).
  • Prefixes: Indicate the number of atoms (mono-, di-, tri-, tetra-, penta-, etc.) (e.g., carbon dioxide, CO₂).