GNS

• Matter


  Anything that occupies space and possesses mass of its own
• Matter


  • Can exist as living and non-living entity
  • Living matter has properties of respiration, growth, movement, metabolism, and reproduction
  • Non-living matter does not exhibit the above properties
  • Growth in non-living matter only comes if there is an addition of the same or different matter
• Composition of matter


  • Pure substances
  • Mixtures
• Physical states of matter

  • Solid
  • Liquid
  • Gas
  • Plasma
• Theory


  A statement of facts for understanding, explaining and making predictions about an observable phenomenon
• Scientific law


  A statement of fact that has been subjected to critical analysis, experimentation and found to correctly explain an observable phenomenon under condition(s) stated
• Types of matter


  • Elements
  • Compounds
  • Mixtures
• Element


  Has only one type of atom
• Compound


  Has more than one type of atom bonded together chemically
• Mixture


  Made up of more than one element or compound in a weak bond that requires no chemical process to separate, but requires only a simple physical procedure
• Homogeneous mixture


  A solution (e.g. salt in water) or air mixture (e.g. mixture of N2, O2, CO2, H2O)
• Heterogeneous mixture


  Such as chocolate or soil
• Kinetic theory


  Explains the behaviour of matter by understanding its state or motional behaviour
• Assumptions of kinetic theory


  • Particle dimension is much less than the distance between collisions
  • Particle velocity is large such that there are many collisions occurring in a short time interval
  • Separation between particles is large such that mutual columbic (charged particle) forces of attraction or repulsion are negligible
  • Collisions between particles are perfectly elastic
  • Particles have no sense of history between collision
  • Motion is random
• Solid


  • Particles only vibrate and rotate about a mean position
• Liquid


  • Particles vibrate and rotate about a mean position but can also easily slide over each other
• Gas


  • Particles move randomly and are translated from one place to another
• Subatomic particles


  • Protons
  • Neutrons
  • Electrons
• Hydrogen is the smallest atom having nuclear particle of one proton and an electron moving round it in spherical orbit
• More complicated nucleons have electrons moving in elliptical orbits
• Sublimation


  The process of change from solid to gas without passing through the liquid state
• Substances that sublime


  • Iodine
  • Ammonium chloride
• All physical change involves change of state
• Matter changes from solid to liquid and to gas
• In few cases, matter changes from solid to gas without passing through liquid state
• Subatomic particles


  Particles revealed by probes made using x-rays, beyond the atomic study
• Atomic models


  • Constructed by Rutherford and Bohr
  • Showed that the atom had a small positively charged nucleus surrounded by electrons
• Hydrogen atom


  Smallest atom having nuclear particle of one proton and an electron moving round it in spherical orbit
• Subatomic particles


  • Proton
  • Neutron
  • Electron
• Proton


  Positive charge (+1), mass 1.673 x 10-27kg
• Neutron


  Neutral charge (0), mass 1.675 x 10-27kg
• Electron


  Negative charge (-1), mass 9.1 x 10-31kg
• Charge of 1e = 1.602 X 10-19 Coulombs
• A neutral atom always has equal number of protons and electrons since the neutron has no charge
• Positive and negative charges attract each other, while two similar charges repel each other
• States of matter


  • Solid
  • Liquid
  • Gas
  • Plasma
• Matter is capable of change from one physical state to another due to temperature change
• Nuclear change


  Involves either fission (splitting) of the nucleus of an atom, or fusion (combining) of neutrons and protons to form heavier atoms
• Nuclear change involves about 1,000,000 times as much energy as a chemical change
• Radioactive elements


  Elements that undergo nuclear change and emit radiation