Physical Science Semester 2 review

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Physical Science Semester 2 review
2013-05-20 06:48:15
Physical Science

Semester 2 review
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  1. Hypothesis
    Possible explanation for a problem using what is known and what is discovered
  2. Independent Variable
    Factor that as it changes affects the measure of another variable
  3. Dependent Variable
    Its value changes according to the changes in other variables
  4. Control
    Standard by which the test results can be compared
  5. Theory
    An explanation of things or events based on knowledge gained from many observations and investigations
  6. Scientific Law
    A statement about what happens in nature and that seems to be true all the time
  7. Reactant
    Starting substances that react
  8. Products
    the new products produced
  9. Chemical Reaction
    A change where one or more substances are converted into new substances
  10. Coefficients
    Represents the number of units each substance taking part in a reaction
  11. Balanced Chemical Equation
    A chemical equation with the same number of atoms of each element on both sides of the arrow
  12. Combustion Reaction
    Occurs when a substance reacts with oxygen to produce energy in the form of heat and light
  13. Synthesis Reaction
    • Two or more substances combine to form another substance
    • A+B=AB
  14. Decomposition Reaction
    • separation of a substance into two or more substances that may differ from each other and from the original substance
    • AB-> A+B
  15. Single-Displacement Reaction
  16. Double-Displacement Reaction
    Takes place if a precipitate, gas, or a gas forms when two ionic compounds in a solution are combined
  17. exergonic reactions
    Chemical reaction that releases energy
  18. exothermic reaction
    energy given off primarily in the form of thermal energy
  19. endergonic reaction
    More energy is required to break bonds than is released when new ones are formed
  20. Endothermic Reaction
    more energy is required to break bonds than is released when new ones are formed
  21. Endothermic Reaction
    When energy is needed to keep a reaction going is in the form of thermal energy
  22. Collision Model
    States that atoms, ions, and molecules must collide in order to react
  23. Acid
    substance that produces hydrogen ions in a solution
  24. base
    a substance that produces hydroxide ions when dissolved in water
  25. pH
    Measure of the concentration of H+ ions in solution
  26. hydroxide ion
    contained in most bases
  27. hydronium ion
    interacts with water molecules in acids
  28. -Taste: Sour
    -Some can damage tissue by producing painful burns
    -React strongly with certain metals
    Common In:
                 -Citrus Fruits
                 -Yogurt and buttermilk
                 -Produced in muscles during high
                  level of exercise
                 -Sulfuric, Phosphoric, Nitric, and 
    Properties of Acids
  29. Taste: Bitter
    -Crystalline Solids
    -Chemical Burns
    -React strongly with certain metals
    Common In:            
    -Citrus Fruits            
               - Cleaning Products
    Properties of Bases
  30. Catalyst
    Substance that speeds up a chemical reaction without being permanently changed itself
  31. Distance
    the length an object travels, measured in SI units
  32. Displacement
    the distance and direction of the objects change in position
  33. Speed
    Distance traveled in X amount of time
  34. Instantaneous Speed
    Instant increase in speed