Reaction Types February 2015

Balance the following equation. N2H4 (g) + N2O4 (g)  H2O (l) + N2 (g) 2 N2H4 (g) + N2O4 (g)  4 H2O (l) + 3 N2 (g)

Types of Reactions Five Types Synthesis Decomposition Single Replacement Double Replacement Combustion (Complete and Incomplete)

Synthesis Reactions A reaction in which two or more reactants react to form one product A + B  C Examples: 2 Na(s) + Cl2 (g)  2 NaCl (s) CaO (s) + H2O (l)  Ca(OH)2 (s) 2 SO2 (g) + O2 (g)  2 SO3 (g)

Synthesis - Two people go on a date and become a couple.

Decomposition Reactions A single compound breaks down into two or more elements or new compounds C  A + B Usually happens when substances are heated Examples: 2 Na3N (s)  6 Na (s) + N2 (g) CaCO3 (s)  CaO (s) + CO2 (g)

Decomposition - A couple breaks up and goes their separate ways

Single-Replacement Reactions The atoms of one element replace the atoms of another element in a compound. A + BX  AX + B Metals will replace hydrogen or another metal depending on the activity series Nonmetals will replace other nonmetals, mostly halogens based on reactivity Example: 2 AgNO3 (aq) + Cu (s)  Cu(NO3)2 (aq) + 2 Ag (s)

The activity series is used to help determine if a chemical reaction will occur. The metal or halogen must be more active than the metal or halogen it is trying to replace. The activity series is also used to predict products. Hydrogen is in between lead and copper

Will a reaction occur in the following? Cu (s) + AgNO3 (aq)  ? Fe (s) + Na3PO4 (aq)  ? Ag (s) + AlCl3 (aq)  ? Cl2 (g) + HF (aq)  ? F2 (g) + NaBr (aq)  ?

Double - Replacement Reactions An exchange of ions between two compounds AX + BY  AY + BX Example 2 NaOH (aq) + CuCl2 (aq)  2 NaCl (aq) + Cu(OH)2 (s) All DR reactions produce either water, a precipitate, or a gas. A solid produced during a chemical reaction in a solution is called a precipitate

Write the balanced chemical equations for the following DR reactions Aqueous lithium iodide and aqueous silver nitrate react to produce solid silver iodide and aqueous lithium nitrate. Aqueous barium chloride and aqueous potassium carbonate react to produce solid barium carbonate and aqueous potassium chloride. Acetic acid and potassium hydroxide react to produce potassium acetate and water.

Answers LiI (aq) + AgNO3 (aq)  AgI (s) + LiNO3 (aq) BaCl2 (aq) + K2CO3 (aq)  BaCO3 (s) + 2 KCl (aq) HC2H3O2 (aq) + KOH (aq)  KC2H3O2 (aq) + H2O (l)

Combustion Reactions When oxygen combines with a substance and releases energy in the form of heat and light A + O2  AO When hydrocarbons burn they form CO2 and H2O Complete form CO2 and H2O Incomplete form CO and H2O Example: C3H8 (g) + 5 O2 (g)  3 CO2 (g) + 4 H2O (g) 4 Fe (s) + 3 O2 (g)  2 Fe2O3 (s)