Chemical Reactions

REACTANTS AND PRODUCTS
• A chemical reaction is a well defined example of a chemical change
• The substances that are about to react are the reactants
• The new substances produced are the products
• They are related by the equation
  
  reactants products

CONSERVATION OF MASS

• In a chemical reaction, matter is not created nor destroyed
• Matter is conserved
• Mass of reactants = mass of products

DESCRIBING CHEMICAL REACTIONS

• Coefficients represent the relative amounts of substances taking part in a reaction
• state symbols describe the states of matter of the substances in the reaction
  1. (aq) - aqueous dissolved in water
  2. (l) - liquid
  3. (g) - gaseous
  4. (cr) - crystalline solid
     • if a product, indicates that a precipitate has been formed

TYPES OF REACTIONS

1. Synthesis
   • two or more substances join to form one product
     A + B AB
2. Decomposition
   • One reactant breaks down to form two or more products
     AB A + B
3. Single Displacement
   • One element replaces another in a compound
     A + BC AC + B
     or

     D + BC BD + C

4. Double Displacement
   • two compounds react to form two different compounds
   • The positive part of the 1st compound combines with the negative part of the second compound (They swap partners)
     AB + CD AD + CB
   • A precipitate, water or gas is produced when two ionic compounds combine

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