Chapter 6 Section 3 Controlling Chemical Reactions by hcj


									             Bell Ringer                  4-29-09
1.   When we balance equations, we only change _________, not
2.   T/F: Balanced chemical equations should have the same number of
     atoms on each side of the arrow.
3.   Chemical equations are just abbreviations using chemical
     _______ and numbers.
4.   In 2C6H2O5, how many atoms of Hydrogen are there?
               ALCOS Objectives:

 #1- Identify the steps of the scientific method
 #4 State the law of conservation of matter

  (Balancing Chemical Equations)
     Chapter 6 Section 3
Controlling Chemical Reactions
    To start a chemical reaction you need
    activation energy.

    Activation energy is the minimum amount
    of energy needed to start a chemical
 Exothermic Reactions
 Endothermic Reactions

 P. 206 in textbook
   Chemical reactions do not all occur at the same

 Explosions  really fast
 Rusting  much slower
                             Rate of Reaction
   Rate of reaction tells us how fast a reaction occurs.

   To find the rate of reaction, you can measure either how quickly the
    reactant is disappearing or how quickly the product is appearing.

   Ex. If it takes 1 minute for 2 inches of the candle to burn, how many
    minutes will it take for 6 inches of the candle to burn.

   Ans. 3
What affects the rate of reaction?

   Concentration- the amount of substance present.

   Surface area – how big or small the area is or how
       much is being exposed

   Temperature – hot or cold
Inhibitor – slows down a chemical reaction. (ex:
food preservatives)

Catalyst – speeds up a chemical reaction. (ex:

Ex. Enzymes – breaks down food. Make it possible
for your body to function properly.

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