Net Ionic Equations 8 4 Show only the

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Net Ionic Equations (8 -4) • Show only the species (atoms/ions) participating in a

Net Ionic Equations (8 -4) • Show only the species (atoms/ions) participating in a reaction o Single displacement reaction – exchange electrons o Double displacement reaction – form new bonds (ionic or covalent) • Steps 1. From formula equation write complete ionic equation • use ion symbols for aqueous species • use element, formula symbols for (g), (l), (s) 2. Cancel spectator ions (ions not forming new bonds)

Can be written for: o Single Displacement Reactions (electron transfer reactions) • One spectator

Can be written for: o Single Displacement Reactions (electron transfer reactions) • One spectator ion • Charges must balance o Double Displacement Reactions (bond forming reactions) • Two spectator ions • Charges on reactants side must sum up to zero

To predict the products of single-replacement reactions. Refer to the activity series (page 281

To predict the products of single-replacement reactions. Refer to the activity series (page 281 or appendix A, page 832) • Is the free element above the element to be replaced in the compound? • If yes, the reaction will occur • Is the free element below the element to be replaced in the compound? • If yes, then a reaction will NOT occur The more active an element is, the more likely it will form compounds!

Simple Activity Series of Metals Decreasing Reactivity K Ca Na Mg Al Zn Fe

Simple Activity Series of Metals Decreasing Reactivity K Ca Na Mg Al Zn Fe Ni Pb H 2 Cu Ag Au Activity Series of Halogens Decreasing Reactivity Increasing Reactivity F 2 Cl 2 Br 2 Increasing Reactivity

Example – Single Displacement Check Activity Series first! Formula Equation: Cu (s) + 2

Example – Single Displacement Check Activity Series first! Formula Equation: Cu (s) + 2 Ag. NO 3 (aq) Cu(NO 3)2 (aq) + 2 Ag (s) Complete Ionic Equation: Cu (s) + 2 Ag 1+ (aq) + 2 NO 31 - (aq) Cu 2+ (aq) + 2 NO 31 - (aq) + 2 Ag (s) Identify Spectator Ion: NO 31 - is found on both sides of the yields sign and will cancel out. Net Ionic Equation: Cu (s) + 2 Ag 1+ (aq) Cu 2+ (aq) + 2 Ag (s) Note that charges balance. There are 2(+) charges on the reactants side and 2(+) charges on the products side.

A Precipitation Reaction must produce a new solid substance. Use solubility rules (p. 284)

A Precipitation Reaction must produce a new solid substance. Use solubility rules (p. 284) to decide whether a precipitation will take place: • Reactants are usually all soluble ionic compounds (will dissolve easily in water). • If one of the ions from reactant #1 will form an insoluble compound with an ion from reactant #2, a precipitation reaction will take place. (Insoluble means will not dissolve in water. )

Some Simple Solubility Rules • • All compounds of Group 1 and NH 4+

Some Simple Solubility Rules • • All compounds of Group 1 and NH 4+ are soluble. All nitrates are soluble. All halides, except those of Ag+ and Pb 2+, are soluble. All sulfates, except Ca 2+, Sr 2+, Ba 2+, Hg 22+, and Pb 2+ are soluble. • All carbonates, except those of Group 1 and NH 4+, are insoluble. • Most hydroxides, except those of Group 1 and NH 4+, are insoluble.

Example – Double Replacement Formula Equation: Ag. NO 3 (aq) + Na. Cl (aq)

Example – Double Replacement Formula Equation: Ag. NO 3 (aq) + Na. Cl (aq) Ag. Cl(s) + Na. NO 3 (aq) Complete Ionic Equation: Ag 1+ (aq) + NO 31 - (aq) + Na 1+ (aq) + Cl 1 - (aq) Ag. Cl (s) + Na 1+ (aq) + NO 31 - (aq) Identify Spectator Ions: Na 1+ and NO 31 - are found on both sides of the yields sign and will cancel out. Net Ionic Equation: Ag 1+ (aq) + Cl 1 - (aq) Ag. Cl (s) Note that charges balance. There is a net zero charge [(1+) + (1 -)] on the reactants side and zero charge on the products side.