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Types of Reactions. Synthesis: 2 or more reactants form one product Metal + nonmetal → binary salt 6 Li + N 2 → 2 Li 3 N Metallic oxide + water → Base Na 2 O + H 2 O → 2NaOH Nonmetallic oxide + water → acid N 2 O 5 +H 2 O → 2HNO 3 Metallic oxide + nonmetallic → salt
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Types of Reactions • Synthesis: 2 or more reactants form one product • Metal + nonmetal → binary salt • 6 Li + N2 → 2 Li3N • Metallic oxide + water → Base • Na2O + H2O → 2NaOH • Nonmetallic oxide + water → acid • N2O5 +H2O → 2HNO3 • Metallic oxide + nonmetallic → salt • CaO +SO3 → CaSO4 • Decomposition: one reactant is broken down into two or more products • Often heating causes this reaction • A sample of sulfurous acid is heated: H2SO3 → H2O + SO2
Types of Reactions: Replacements • Single Replacement • One element replaces one part of a compound • Use activity series • Metal (most common in exercises) : Li>Ca>Na>Al>Zn>Fe>Pb>[H2]>Cu>Ag>Pt • Nonmetal (most common) F2>Cl2>Br2>I2 • The more active replaces the least active • The more active metal replaces • Less active metals in salts 3Mg + 2FeCl3 → 3MgCl + 2Fe • Hydrogen in acids 2Li + 2HCl → H2 + LiCl • Hydrogen in water 2Na + H2O → 2NaOH + H2 • Active nonmetals replace less active nonmetals • Cl2 + 2KI → 2KCl + I2
Types of Reactions: Replacements • Double: the cations and anions switch partners • AX + BY → AY + BX • Driving force: the removal of at least a pair of ions from the solution • Formation of a precipitate • Memorize solubility chart - NO ALTERNATIVE! • Al2(SO4)(aq) + 6NaOH(aq)→ 2Al(OH3)(s) + 3Na2SO4(aq) • Formation of a gas • Common gases: H2S; CO2; SO2; NH3 • these are often a two step reaction with the formation of a substance that breaks down • Na2SO3(aq)+HCl(aq)→ H2O(l) +SO2(g) + 2NaCl (aq) • Really: Na2SO3+HCl → H2SO3 + 2NaCl → H2O +SO2 + 2NaCl • Formation of primarily molecular species • Ca(CH3COO)2(aq) + 2 HCl(l) → CaCl2(aq) + CH3COOH(aq)
Double replacement & acid-base neutralization • Acid + base → salt + water • HA + BOH → AB + HOH • Check solubility rules for the salt! • Polyprotic acids are tricky; if the base is in excess then neutralization occurs • Dilute sulfuric acid is reacted with excess sodium hydroxide: H2SO4(aq)+ 2NaOH(aq) → Na2SO4(aq) + 2H2O(l) • Equal moles of sulfuric acid is reacted with sodium hydroxide: H2SO4(aq)+ NaOH(aq) → NaHSO4(aq) + H2O(l)
