Page 381 - Chemistry eBook

Spontaneous Reactions Vs. Nonspontaneous Reactions
SPONTANEOUS REACTIONS: Reactions that happen on their own (under specific conditions)
• When a more active metal replaces a less active metal (in a single
replacement), the reaction is spontaneous.
Zn + CuNO3 ZnNO3 + Cu
Zn replaced Cu. Since Zn is higher on Table J, and more active than Cu, the reaction is spontaneous.
NONSPONTANEOUS REACTIONS: Reactions that do not happen on their own • When a less active metal replaces a more active metal (in a single
replacement), the reaction is nonspontaneous.
Pb + NiCl2 PbCl2 + NI
Pb (less active) replaced Ni (more active). The reaction is therefore nonspontaneous.
There are many Regents questions on this topic.
When a more active teacher replaces a less active teacher, the class will spontaneously improve. When a more active element replaces a less active element, the reaction will be spontaneous.
UNIT 10: OXIDATION & REDUCTION © 380