Types of Chemical Reactions Single Replacement, Double Replacement, and Combustion Reactions

Single Replacement Reactions

Single Replacement Reactions one element replaces another in a compound metal replaces metal (+) nonmetal replaces nonmetal (-) A + BC  B + AC A + BC  C + BA

Activity Series of Metals & Halogens Single Replacement Activity Series of Metals & Halogens free element must be more active (check activity series) Li K Ca Na Mg Al Zn Fe Pb H Cu Hg Ag F Cl Br I Decreasing reactivity ←

Single Replacement N.R. Cu(s)+ FeSO4(aq) Br2(l)+ NaCl(aq)  Fe(s)+ CuSO4(aq)  Cu(s)+ FeSO4(aq) Br2(l)+ NaCl(aq)  N.R.

Single Replacement Problems 1) Zn(s) + H2SO4 (aq) → 2) Sn(s) + NaNO3 (aq) → 3) Cl2(g) + NaBr(aq) → 4) Mg(s) + LiNO3(aq) → ZnSO4 (aq) + H2 (g) No reaction NaCl (aq) + Br2 (l) No reaction

Double Replacement Reactions

Double Replacement Reactions ions in two compounds “change partners” cation of one reactant combines with anion of the other reactant AX + BY  AY + BX

Double Replacement Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together AgNO3(aq) + NaCl(s)  AgCl(s) + NaNO3(aq) K2SO4(aq) + Ba(NO3)2(aq)  KNO3(aq) + BaSO4(s) 2

Double Replacement Products one product is insoluble and precipitates (check solubility table) Na2S(aq) + Cd(NO3)2(aq) → CdS(s) + NaNO3(aq) 2 NaNO3(aq)+ KI(aq)  NaI(aq) + KNO3(aq) No precipitate – No reaction

Double Replacement Products One product is a gas that bubbles out of the mixture 2 NaCN(aq) + H2SO4(aq) → 2 HCN(g) + Na2SO4(aq) NaHCO3(aq) + HC2H3O2(aq) → H2CO3(aq) + NaC2H3O2(aq) ↓ CO2(g) + H2O(l)

Double Replacement Products One product is a molecular compound such as water Example: An antacid neutralizes stomach acid. Ca(OH)2(aq) + HCl(aq) → 2 CaCl2(aq) + H2O(l) 2

Double Replacement Practice Predict the products. Determine the precipitate. HCl(aq) + AgNO3(aq)  CaCl2(aq) + Na3PO4(aq)  Pb(NO3)2(aq) + BaCl2(aq)  FeCl3(aq) + NaOH(aq)  H2SO4(aq) + NaOH(aq)  KOH(aq) + CuSO4(aq)  HNO3(aq) + AgCl(s) Ca3(PO4)2(s) + NaCl(aq) PbCl2(s) + Ba(NO3)2(aq) Fe(OH)3 (s) + NaCl (aq) H2O (l) + Na2SO4 (aq) K2SO4 (aq) + Cu(OH)2(s)

Going Backwards… Fill in the appropriate reactants based on the given products. 1) → AgBr(s) + KNO3(aq) 2) → BaSO4(s) + 2NaCl(aq) 3) → KCl(aq) + CaSO4 (s)

Combustion Reactions

A + O2  B S(s) + O2(g)  SO2(g) Combustion Reactions the burning of any substance in O2 to produce heat A + O2  B S(s) + O2(g)  SO2(g)

CxHy + O2  CO2 + H2O Combustion Reactions hydrocarbons combine with oxygen to form CO2 + H2O CxHy + O2  CO2 + H2O CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)

Combustion Products in combustion are carbon dioxide and water. (although incomplete burning does cause some by-products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)

Combustion 8 5 6 C5H12(g) + O2(g)  CO2 + H2O 4 2 Na(s)+ O2(g)  Examples 8 5 6 C5H12(g) + O2(g)  CO2 + H2O 4 2 Na(s)+ O2(g)  Na2O(s) 5 3 4 C3H8(g)+ O2(g)  CO2(g)+ H2O(g)

Combustion Practice C6H6 + O2  CH3OH + O2  Mg + O2  CO2 + H2O