TYPES OF CHEMICAL REACTIONS
Synthesis Reaction – also called composition, two or more substances combine to form a more complex substance
A synthesis reaction is like two people who went to a dance separately and leave as a couple. + =
AX A + X Fe + S FeS
Decomposition reaction - a complex substance breaks down to form two or more simpler substances.
A decomposition reaction is like a couple (metal and nonmetal) go to a dance, then break up and leave as single people. = +
AX A + X 2H2O 2H2 + O2
Single Replacement – One substance is displaced (moved) from its compound by another substance.
Single replacement is like a couple who go to a dance together, but break up and one of them leaves with someone else.
Single Replacement + +
Remember, metals combine with nonmetals Remember, metals combine with nonmetals. If one thing is replaced, it is replaced by another thing like it. Metal Nonmetal + Metal Metal Nonmetal Metal +
+ Metal Nonmetal Nonmetal Nonmetal + Metal Nonmetal
+ + - + - + A + BX AX + B or - + - + - - A + BX BA + X
+ + - + - + Fe + CuS FeS + Cu or - + - + - - Cl2 + 2KI 2KCl + I2
Double Replacement – The substances change places Double Replacement – The substances change places. Remember, metals bond with nonmetals!
A double replacement reaction is like two couples who go to a dance A double replacement reaction is like two couples who go to a dance. During the dance, they break up. Then they leave with the opposite member of the other couple. REMEMBER: Metals bond with nonmetals! Check the valences!
Double Replacement + +
Double Replacement + - + - + - + - Na2S + AgCl2 2NaCl + AgS
Be + Li2O BeO + 2Li 2Mg + 2Cl2 2MgCl2 CaI2 Ca + I2 BaF2 + Na2S Single Replacement Be + Li2O BeO + 2Li Synthesis or Composition 2Mg + 2Cl2 2MgCl2 Double Replacement BaF2 + Na2S BaS + 2NaF Decomposition CaI2 Ca + I2 Single Replacement 2K2O + 2Cl2 4KCl + O2