CC1-?

• States of matter


  Solid, liquid, gas
• Melting and freezing


  1. Solid → liquid: melting

  2. Liquid → solid: freezing
• Boiling and condensing


  1. Liquid → gas: boiling

  2. Gas → liquid: condensing
• Particle model


  • Particles represented by small solid spheres
• Why do gas particles have the most energy?

  Gas particles have the most energy because they move quickly in random directions as they are spread far apart
• Why do Liquids have more energy than solid but less than gas

  Particles have more energy than solid less than gas as they are able move around to an extent and are not fixed in place
• Solid


  Particles have the least energy, fixed in place
• State changes (melting, boiling, freezing, condensing) are physical changes - they involve the forces between the particles but the particles themselves don't change
• Chemical changes are where a new product has been formed
• What do the strength's of forces between particles determine?

  Determines melting point and boiling point of a substance
• The nature of the particles([properties of the substance e.g boiling point) involved depends on the type of bonding and the structure of the substance
• Predicting physical state of a substance

  1. At temperatures below melting point, substance will be solid

  2. At temperatures above melting point but below boiling point, substance will be liquid

  3. At temperatures above boiling point, substance will be a gas
• what is a Molecule?

  A group of two or more atoms that are held together by chemical bonds
• what are some examples of molecules(hint- O2, H20, N2, Cl, C02)

  • Oxygen
  • Water
  • Nitrogen
  • Chlorine
  • Carbon dioxide
• What is a Compound?

  A substance that contains two or more different elements, with the atoms held together by chemical bonds
• Compounds always contain two or more different elements
• What are Chemical formulas and what are they used to represent

  chemical symbols and numbers to represent the formation of a compound
• Chemical formulas


  • H2O
  • CO2
  • H2SO4
  • Ca(OH)2
• What is a Mixture?

  Two or more substances that are not chemically combined, just physically mixed together
• Mixtures can be separated using physical methods like filtration, crystallization or distillation