Redox Reactions Chapter 7

Redox Reactions Oxidation-Reduction (Redox) Reactions Redox reactions involve an electron transfer. These reaction occur between metals and nonmetals. Ionic reactions are redox reactions.

The name There are two parties in a redox reaction. The one that is gaining electron(s). This one gets reduced. Think of the charge, it gets lower. The one that is losing electron(s). It gets oxidized.

Single Replacement Reaction Your book calls this a single displacement reaction. ~an atom or group switches its partner AX + B  A + BX AgCl + Zn  Ag + ZnCl CuSO 4 + Fe  FeSO 4 + Cu FeO + Al  Al 2 O 3 + Fe

What makes this a redox reaction? Follow the electron AgCl + Zn  Ag + ZnCl Zinc starts out neutral, Ag is +, Cl is -. The compound is neutral but they still have their charges Then the reaction. Zinc gives an electron to silver making silver neutral, and zinc positive. e-e-

Double Replacement Reaction ~two atoms or groups switches their partners AX + BY  AY + BX 2NiNO 3 + CaSO 4  Ca(NO 3 ) 2 + Ni 2 SO 4 NaCl + AgI  NaI + AgCl All of the precipitation reactions/net ionic equations we have been doing have been double replacement reactions.

Combustion Reaction A chemical reaction involving oxygen that produces energy (heat) so rapidly that it produces a flame. CH 4 + O 2  CO 2 + H 2 O Natural gas combusting. Used for Bunsen burners, gas stoves, gas furnaces etc. C 8 H 18 _ + O 2  CO 2 + H 2 O Combustion of octane (gasoline) H 2 + O 2  H 2 O Combustion of hydrogen, used in a fuel cell

Synthesis (combination) Reactions ~simpler molecules build together and form more complex molecules A + B  X 6 CO H 2 O  C 6 H 12 O O 2 4 Zn + O 2  2 Zn 2 O

Decomposition Reactions ~more complex molecules break apart to form simpler molecules X  A + B C 6 H 12 O O 2  6 CO H 2 O 2 H 2 O  2 H 2 + O 2

Flow Chart Reactions Precipitation Single/Double Replacement Redox Singe/Double ReplacementDecompositionCombustionSynthesis Acid Base

Reactions don’t fit into just one category Most fit into several of these. 2 H 2 + O 2  2 H 2 O This is a combustion reaction, and a synthesis reaction.

Identify the type of reaction Mg + 2 HNO 3  Mg(NO 3 ) 2 + H 2 Redox, Single replacement C 8 H 18 + O 2  CO 2 + H 2 O Combustion, Decomposition FeO + HCl  FeCl 2 + H 2 O Acid Base, Double replacement Fe + O 2  Fe 2 O 3 Synthesis (combustion)

Continued K 3 PO 4 + Ca(SO 4 )  K 2 SO 4 +Ca 3 (PO 4 ) 2 Double replacement Fe + HCl  H 2 + FeCl 2 Single replacement, acid base C 3 H 5 (NO 3 ) 3  N 2 + O 2 + CO 2 + H 2 O Decomposition Cu + O 2  CuO Synthesis