Summative reviewer science

• Anything that has mass and occupies space is called matter
• Matter- made up of atom
• Atom- from greek word "atomos" which means indivisible particle
• Leucippus & Democritus- 2, 500 years ago they believed that nature is considered of matter
• John Dalton- 19th century, said that all matter is composed of atom
• Molecules- combined atoms
• Chemical property- depends on how substance react to another substance
• Intensive property- color, melting point, boiling point, density
• Extensive property- based on amount of substance such as mass, volume, length, and shape
• Mass- amount of matter
• Volume- space occupied
• Physical change- occurs when matter changes in state or appearance without changing its original composition
• Physical change- it is also a phase change, change from one-state to another (Ex. boiling, melting, freezing, shredding)
• Chemical change- occurs when matter changes its composition which may result to the formation of a new substance
• Chemical change- we can no longer determine the original property of a substance since the resulting new substance will have its own unique property
• Chemical change- ex. Burning, cooking, rustling, rotting
• Rotting


  A chemical change
• Indicators for chemical change


  • Gas is created
  • An odor is created
  • The color of substance changes
  • Sound is generated
  • There is a shift in the temperature. The environment either heats up or cools down
  • Light is generated
  • A precipitate develops
• Reversing the change is difficult or impossible
• Temperature measure


  How hot or cold something is
• Boiling point


  • The temperature at which vapor pressure is equal to atmospheric pressure
• Evaporation/Vaporization


  The liquid phase passes into the gas phase (e.g. alcohol to vapor)
• Vapor pressure


  Uses liquid to become gas
• Freezing


  The process of changing liquid to solid state (e.g. ice cream)
• Melting


  Solid is changed to liquid (e.g. melting candle)
• Condensation


  Gas changes to liquid phase (e.g. water droplets on the glass of cold water)
• Sublimation


  Solid changes directly to gas (e.g. dry ice used to create fog)
• Deposition


  Gas changes directly to solid (e.g. silver vapor in vacuum chamber to make solid layer for mirror)
• Density


  A measure of how "tightly packed" an object is
• Specific gravity


  A ratio between the density of a substance and the density of another substance
• Specific gravity


  • Density of ice (0.92) / density of water (1.00) = 0.92, meaning 92% of ice will submerge in water
• Atoms are the smallest particle of an element and matter
• Molecules are complex structures made of atoms
• Atoms


  • Spherical, made of protons, electrons, and neutrons
• Atoms


  • H2O (water molecule)
• Democritus proposed the idea of "atomos" meaning "indivisible"
• J.J. Thomson discovered the electron in his Cathode Ray Experiment and proposed the plum pudding model
• Ernest Rutherford accidentally discovered the proton and the nucleus in his Gold Foil Experiment
• Subatomic particles


  • Electron (e)
  • Proton (p+)
  • Neutron (n0)
• Electron (e)


  Negative charge, mass 9.109x10^-28 kg, located outside the nucleus