Chemical Reactions Reaction Types

Write and classify balanced chemical equations from written descriptions of reactions. Include: polyatomic ions   Predict the products of chemical reactions, given the reactants and type of reaction. Additional KEY Terms

Chemical equation – contains all necessary info about a reaction (like a recipe). + +

The Law of Conservation of Mass: In any chemical reaction matter cannot be created or destroyed. H2 (g) + O2 (g) H2O (g) 2 2 H H O H H O O H H H We call this equation unbalanced because the atoms are not conserved. H O

Balancing Rules: You cannot change the formula of any reactant or product. You can only change the coefficients in front of the reactants and products. 3 H2O

2 HCl + MgBr2 MgCl2 + HBr 2 H: 1 H: 1 (2) = 2 (2) = 2 Cl: 1 Cl: 2 Mg: 1 Mg: 1 Br: 2 Br: 1 (2) = 2 (2) = 2 (2) = 2 (2) = 2 BALANCED

2 2 K(NO3) + Mg Mg(NO3)2 + K K: 1 K: 1 NO3: 1 NO3: 2 Mg: 1 Mg: 1 (2) = 2 (2) = 2 (2) = 2 BALANCED

+ + 2 K2O + Cl KCl + O (s) 2 2 (g) 4 2 (g) +1 -2 +1 -1 potassium Solid potassium oxide and chlorine gas react to produce potassium chloride and oxygen gas. +1 -2 +1 -1 potassium oxide potassium chloride + chlorine + oxygen 2 K2O + Cl KCl + O (s) 2 2 (g) 4 2 (g)

Many reactions are similar. Chemists have classified the 5 types of reactions. BIG PICTURE IDEA: If you know the reactants - you can guess the type of reaction AND predict the products.

Key Words Synthesis reactions Decomposition reactions Single replacement reactions Double replacement reactions Combustion reactions

2 2 4 3 2 K + Cl2 KCl Fe + O2 Fe2O3 Synthesis Reactions (Combination): 2 or more substances react to form a single substance. A + B  C 2 K + Cl2 KCl Fe + O2 Fe2O3 2 4 3 2

C  A + B 2 2 2 3 CO2 CO + O2 Al2S3 Al + S Decomposition Reactions: A single compound splits apart, into two or more simpler compounds. C  A + B CO2 CO + O2 Al2S3 Al + S 2 2 2 3

A + BC  AC + B 2 2 2 2 Single Replacement Reactions: One element replaces another element in a compound. More active elements replace less active elements. A + BC  AC + B 2 2 I2 + CuCl Cl2 + CuI Ba + K(NO3) K + Ba(NO3)2 2 2

AB + CD  AD + CB 2 2 3 3 BaF2 + LiBr BaBr2 + LiF Double Replacement Reactions: 2 compounds split and exchange positive ions AB + CD  AD + CB 2 2 BaF2 + LiBr BaBr2 + LiF HCl + AlBr3 HBr + AlCl3 3 3

CxHy + O2  CO2 + H2O 8 7 3 5 3 4 C7H6O + O2 CO2 + H2O Combustion Reactions: Oxygen reacts with a carbon compound to produce water, carbon dioxide and heat. CxHy + O2  CO2 + H2O C7H6O + O2 CO2 + H2O C3H8 + O2 CO2 + H2O 8 7 3 5 3 4

Synthesis or combination A + B  C Decomposition C  A + B Single replacement A + BC  B + AC Double replacement AC + BD  AD + BC Combustion reactions CxHy + O2  CO2 + H2O

CAN YOU / HAVE YOU? Write and classify balanced chemical equations from written descriptions of reactions. Include: polyatomic ions   Predict the products of chemical reactions, given the reactants and type of reaction.