chem lesson 2

• Chemistry


  The study of matter, its properties, and its changes or transformations
• Matter


  Anything that has mass and takes up space
• Types of matter


  • Solids
  • Liquids
  • Gases
• Mixtures


  • Do not have a single chemical formula
  • Made of more than one pure substance
• Mixtures


  • Pizza
• Pure substances


  • Have a chemical formula
  • Have constant composition and properties
• Pure substances


  • Gold
• Classification of pure substances

  • Element
  • Compound
• Element


  • Consists of only one type of atom
  • Is on the periodic table of elements
• Elements


  • Oxygen (O2)
  • Carbon (C)
• Compound


  • Contains more than one type of atom
  • Has more than one element in the formula
• Compounds


  • Water (H2O)
  • Methane (CH4)
• Types of mixtures


  • Heterogeneous mixture (Mechanical mixture)
  • Homogeneous mixture (Solution)
• Heterogeneous mixture


  Two or more substances can be seen
• Heterogeneous mixtures


  • Oatmeal & Raisins
  • Oil and Water
• Homogeneous mixture (Solution)


  Two or more substances mix together so completely that it looks like it is made of only one substance
• Homogeneous mixtures


  • Stainless steel
  • Juice
• Practice


  1. State whether each of the following is an element, compound, solution or heterogeneous mixture:

  2. ketchup

  3. carbon

  4. ammonia (NH3)

  5. a book
• Physical property


  A characteristic or description of a substance that may help to identify it
• Physical properties


  • Colour (red, white, colourless)
  • State (solid, liquid, gas)
  • Clarity (transparent, translucent, opaque)
  • Form (powder, crystals, sheet, pebble-like, ribbon)
  • Lustre (dull, shiny)
• More examples of physical properties

  • Conductivity (ability to conduct electricity)
  • Boiling/melting points
  • Density
  • Taste
  • Solubility (ability to dissolve in water)
  • Malleability (ability to bend)
  • Ductility (ability to be drawn into a wire)
  • Viscosity (thickness when poured)
  • Texture (feel)
  • Odour
• Practice


  1. Name the physical property described by each statement:

  2. Aluminum can be hammered into thin sheets

  3. Copper wire is used for electrical circuitry in homes

  4. Sugar is crystalline

  5. Ice melts at 0°C

  6. Diamond is a colourless solid
• Physical changes


  • No new substance is formed
  • The molecules maintain their structure, but may change in state or form
• Examples of physical changes


  • Change of state (melting, freezing, vaporization, condensation, sublimation)
  • Creating a mixture (e.g. dissolving)
  • Physically breaking something
• IRON


  • OXYGEN GAS
  • RUST (Iron Oxide)
• Chemical changes


  • A new substance is formed
  • The new substance has a different molecular structure with different properties
• Clues for a chemical change

  • Colour change
  • Precipitate (solid) formation
  • Production of gas (bubbles)
  • Energy changes (heat, light etc.)
• Practice


  1. Classify each as physical (P) or Chemical (C) change:

  2. a green coating forms on a copper statue

  3. sweat evaporates from your body

  4. a rose bush grows from a seed

  5. juice crystals dissolve in water