Physical and Chemical Changes, Endothermic and Exothermic, and How to Balance an Equation!

I. Matter Can Undergo 3 Types of Changes:
     1. Physical Changes
          A. Change of state: (s) (l) (g) (aq)

          B. No new substances are produced
     2. Chemical Changes
          A. New substances are formed
          B. The new substances also gain new properties
               Ex. Conductivity, acidity, color
               Ex. Burning wood, iron rusting, digesting food
     3. Nuclear Changes
          A. Involves the fusion or fission of a nucleus or an atom
               a. Fusion: the combining of a nucleus or an atom
               b. Fission: the splitting of a nucleus or an atom

II. Energies Associated with each Phase Change
     1. Endothermic: to gain energy
          a. Sublimation, melting, and evaporation are endothermic
     2. Exothermic: to produce energy
          A. Freezing, condensation, and sublimation/deposition are exothermic

III. Balancing Chemical Equations
     1. Matter cannot be destroyed nor created therefore all the matter in the reactants 
     should be equal to the matter in the products
     2. Make an element inventory
          A. List all the elements and how many of them you have on the reactant side and on
          the product side in a T-chart
     3. Write numbers in front of each element until there is the same amount of that element
     on both sides of the equation and on the T-chart
       Ex.
          
     B. Tips
          a. Balance elements in elemental form last
          b. Balance polyatomic ions as a group- only if they do no break apart!
          c. Balance oxygen and hydrogen last

-Nicole