Chemistry Chapter 1 Quiz

Particle Theory of Matter

• All matter is composed of particles, which are in constant motion.
• Different substances consist of different types of particles.
• Increasing temperature speeds up particle motion.
• Particles exert attractive forces on one another.

Pure Substances and Mixtures

• Pure substances consist of one type of particle, e.g., 24k gold, distilled water.
• Mixtures contain two or more types of particles, e.g., hot chocolate (cocoa powder, sugar, milk).
• Two main types of mixtures:
  • Mechanical (heterogeneous): visibly different particles (e.g., solids).
  • Solution (homogeneous): particles are uniformly mixed and not visible (e.g., liquids).

Properties of Gases and Metals

• Gases can form mechanical mixtures (e.g., fog) or solutions (e.g., air).
• Metals can be solutions known as alloys.

Physical Properties

• Provide sensory information and can be classified as:
  • Qualitative: no numerical value (e.g., color, smell).
  • Quantitative: measurable with numerical value (e.g., mass, volume).
• Examples of physical properties:
  • Luster: shininess versus dullness.
  • Clarity: ability to transmit light (opaque, translucent, transparent).
  • Brittleness: tendency to break versus flexibility.
  • Viscosity: thickness of fluids (e.g., honey is more viscous than water).
  • Hardness: ability to scratch or be scratched (diamonds are very hard).
  • Malleability: capability to be shaped (e.g., foil is malleable; glass is brittle).
  • Ductility: ability to be drawn into wires (e.g., copper).
  • Conductivity: ability to transmit electricity (e.g., copper is conductive; plastics are not).

Physical Changes

• Substantial changes occur without altering the chemical composition.
• Examples include state changes (ice to water), size changes (cutting paper), and dissolving in water.

Chemical Properties and Changes

• Chemical properties relate to a substance's reactions and potential new substances.
• Signs indicating a chemical change:
  • Color change indicating a new substance.
  • Smell change due to new substances emitted.
  • Bubbles forming from gas production not from heat.
  • Formation of a precipitate (solid) in a mixture.
  • Temperature or light changes during the reaction.

WHMIS (Workplace Hazardous Materials Information System)

• Communicates hazards associated with materials to ensure safe handling.
• Types of labeled hazards:
  • Flammable: materials that catch fire easily (e.g., gasoline).
  • Oxidizing: substances that support combustion (e.g., bleach).
  • Compressed gases: can explode under heat (e.g., propane).
  • Corrosive substances: can cause chemical burns (e.g., sulfuric acid).
  • Explosive materials: may explode if handled improperly (e.g., sodium metal).
  • Toxic substances: immediate toxic effects (e.g., carbon monoxide).
  • Health hazards: cause long-term health issues (e.g., asbestos).
  • Harmful substances: less severe effects (e.g., epoxy glues).
  • Aquatic toxicity: can harm marine life.
  • Biohazardous materials: cause disease transmission (e.g., fungi).

Characteristic Physical Properties

• Unique to substances and help in identification without changing the composition.
• Melting point: temperature solid turns to liquid.
• Boiling point: temperature liquid turns to gas.
• Freezing point: temperature liquid turns to solid.
• Different substances have specific melting and boiling points (e.g., nitrogen at -196°C; butter at 36°C).

Density

• Density is the ratio of mass to volume, typically measured in g/cm³ for solids and g/ml for liquids.
• Calculating density:
  • Mass can be measured with scales (units: g, mg, kg).
  • Volume can be measured through:
    • Calculation (length × width × height)
    • Graduated cylinder (for liquids)
    • Water displacement (1 ml = 1 cm³).
• Formula for density: Density = Mass / Volume.