1. Chemical Reactions Unit 7 1

2. Chemical Equations 2 FeO 2 (s) + 2 H 2 (g)  Fe (s) + 2 H 2 O (l) NaCl (aq) + AgNO 3 (aq)  AgCl (s) + NaNO 3 (aq) Symbol Found in Chemical Equation Physical Meaning  Produces - equivalent to an equal sign in an algebraic expression +Reacts with or is produced with (s)Compound is a solid (l)Compound is a liquid (g)Compound is a gas (aq)Compound is aqueous (dissolved in water Reactants  Products

3. Chemical Equations 3 A chemical equation is a representation for a chemical reaction that uses chemical symbols and chemical formulas instead of words to describe the change that occurs in a chemical reaction. 2 Mg + O 2  MgOMg + Cl 2  MgCl 2 Reactants  Products Conservation of Matter! Remember that atoms cannot be created or destroyed!

4. Balancing Chemical Equations 4 CH 4 + O 2  CO 2 + H 2 OFe 3 O 4 + H 2  Fe + H 2 O Ca + N 2  Ca 3 N 2 C 4 H 10 + O 2  CO 2 + H 2 O NH 4 NO 3  N 2 + O 2 + H 2 O Remember that atoms cannot be created or destroyed! SCl 2 + NaF  SF 4 + S 2 Cl 2 + NaCl

5. Chemical Equations 5 Synthesis Reactions A single product is produced from 2 or more reactants X + Y  Z SO 3 + H 2 O  H 2 SO 4 Decomposition Reactions A single reactant is converted into 2 or more products Z  X + Y H 2 SO 4  SO 3 + H 2 O

6. Chemical Equations 6 Single Replacement Reactions One element within a compound is replaced with another element XY + Z  ZY + X H 2 SO 4 + Mg 2+  MgSO 4 + 2 H + Double Replacement Reactions 2 compounds switch parts with each other to form two new compounds AB + XY  AX + BY MgSO 4 + CaCO 3  CaSO 4 + MgCO 3

7. Combustion Reactions A substance reacts with O 2 (typically with the help of a flame) 2 C 4 H 10 + 13 O 2  8 CO 2 + 10 H 2 O Chemical Equations 7