GEN SCIENCE AND CHEMISTRY

• Matter


  Anything that takes up space and has mass
• Mass


  A measure of the number of particles in an object
• Weight


  The influence of gravity on mass
• Density


  Calculated using the equation: Density = Mass / Volume
• Units used to calculate density

  • Grams (for mass)
  • Millilitres (mL for volume)
  • Cubic centimetres (cm³)
• There is an exception to the general rule when calculating the density for gases
• Substance


  Any variety of matter with identical properties and composition
• Types of substances


  • Elements
  • Compounds
• Elements


  Cannot be broken down chemically; made up of a particular atom, the basic building block of matter
• Compounds


  Can be broken down chemically; formed from the bonding of two or more elements
• The reaction CH4 + 2O2 → 2H2O + CO₂ shows the elements carbon, hydrogen, and oxygen in different compounds
• Mixtures


  The results of the combination of elements and/or compounds
• Types of mixtures


  • Homogeneous
  • Heterogeneous
• Homogeneous mixtures


  Have only one phase, or have a uniform appearance throughout, and any portion of the sample has the same properties and composition
• Types of homogeneous mixtures

  • Solution
  • Colloid
  • Suspension
• Heterogeneous mixtures


  Mixtures that are made up of more than one phase or of different parts and can be separated physically
• Physical properties


  The observable and measurable properties of substances
• Chemical properties


  The properties observed when a substance reacts with other substances
• Energy


  The ability to do work
• Energy is conserved, that is, it is not created or destroyed
• Joule


  Unit used for measuring amounts of energy
• Calorie


  Unit used for measuring amounts of energy, 1 calorie = 4.18 joules
• Types of energy

  • Potential energy
  • Kinetic energy
  • Sound
  • Light
  • Chemical energy
  • Nuclear energy
• Potential energy


  Stored energy
• Kinetic energy


  Moving energy
• Nature prefers a lower energy state
• Forms of energy

  • Potential
  • Kinetic
• Chemical energy

  The energy stored in the bonds of atoms and molecules
• Nuclear energy

  The energy stored in the nucleus of an atom
• Stored mechanical energy

  Energy stored in objects by the application of a force
• Gravitational energy

  The energy of place or position
• Radiant energy

  Electromagnetic energy that travels in transverse waves
• Thermal energy

  The internal energy in substances; the vibration and movement of atoms and molecules within substances
• Motion

  The movement of objects or substances from one place to another
• Sound

  The movement of energy through substances in longitudinal (compression/rarefaction) waves
• Electrical energy

  The movement of electrons
• Exothermic reaction

  More energy is released than absorbed
• Endothermic reaction


  More energy is absorbed than released
• Energy is always absorbed and released in a reaction
• Activation energy (Ea)

  The energy required to start a reaction