Summary: Classes of Reactions: NON-REDOX
Ion Exchange (or Double Replacement or Double Displacement)
Precipitate Formation; Apply solubility rules to products
salt + salt new salt + new salt
acid + salt new acid + new salt
Acid/Base Reactions; know acid nomenclature
Neutralization
acid + metal hydroxide salt + water
acid + carbonate water + salt + carbon dioxide
Bronsted-Lowry Reactions
acid + water hydronium ion + anion
ammonia + water ammonium + hydroxide ions
Combination
metal oxide + water metal hydroxide
nonmetal oxide + water oxyacid
metal oxide + nonmetal oxide “oxy” salt
Decomposition
metal hydroxide metal oxide + water
oxyacid nonmetal oxide + water
“oxy” salt metal oxide + nonmetal oxide
Summary: Classes of Reactions: REDOX
REDOX
oxidation: increase in oxidation number because electrons are lost
reducing agent is oxidized
reduction: decrease in oxidation number because electrons are gained
oxidizing agent or oxidizer is reduced
SYNTHESIS
metal + nonmetal binary salt
metal + oxygen metal oxide
ANALYSIS
binary salt metal + nonmetal
metal oxide metal + oxygen
COMBUSTION
hydrocarbon + oxygen water + carbon dioxide
SINGLE REPLACEMENT
metal + salt new metal + new salt
nonmetal + salt new nonmetal + new salt
metal + water metal hydroxide + hydrogen gas
metal + acid salt + hydrogen gas
metal hydride + water metal hydroxide + hydrogen gas
Practice: Write balanced chemical equations for the reaction characteristic of each pair of reactants. If the reaction takes place in solution, write the net ionic equation for the reaction also. If a redox reaction occurs, identify the oxidizer.
- solutions of nitrous acid + barium hydroxide
- silver metal is heated in air
- hydrogen chloride gas is bubbled through water
- calcium carbonate is heated (in the absence of air)
- calcium oxide is warmed gently in sulfur trioxide gas
- methane, CH4 gas is ignited in air
- sodium carbonate powder is sprinkled into hydrobromic acid
- bromine is added to a solution of sodium iodide
- zinc metal is dropped into hydrochloric acid
- magnesium oxide is stirred into water
- sulfur dioxide is bubbled into water
- nitric acid + potassium acetate solution
- sodium hydride is dissolved into water
- sodium metal is dropped into water
- copper metal is added to a solution of silver nitrate
Answers:
- 2HNO2 (aq) + Ba(OH)2 (aq) Ba(NO2)2 (aq) + 2HOH(l)
net: 2HNO2(aq) + 2OH-1(aq) 2NO2-1(aq) + 2H2O(l)
-not redox; ion exchange, specifically acid/base neutralization
-driving force is the formation of molecules of water
-nitrous acid is not broken up into ions in the reactants because weak acids do not break up into their ions in large numbers in water solution
- 4Ag(s) + O2(g) 2Ag2O(s)
-redox; synthesis (or combination) reaction, silver is oxidized and thus the reducing agent.
With molecular oxygen being reduced or the oxidizing agent
-ox ½ rxn: 4Ag0 4Ag+ + 4e-
-red ½ rxn: O20 + 4e- 2O2-
-net rxn: 4Ag0 + O20 4Ag+ + 2O2-
- HCl(g) + H2O(l) H3O+1(aq) + Cl-1(aq)
-Bronsted-Lowry transfer of proton from B/L acid to B/L base
- CaCO3(s) CaO(s) + CO2(g)
-not redox; specifically “oxy”salt is decomposed by strong heating into a metallic oxide (or basic anhydride) and a nonmetallic oxides (or acidic anhydride)
- CaO(s) + SO3(g) CaSO4(s)
–not redox; combination, specifically metal oxide and nonmetal oxide “oxy”salt
- CH4(g) + 2O2(g) CO2(g) + 2H2O(l)
–redox; combustion of an organic fuel, oxygen is the oxidizer (or oxidizing agent) and is reduced…carbon looses e-s oxidized from –4 to +4 and is the reducer (or reducing agent)
-also driven by the formation of a gas
- Na2CO3(s) + 2HBr(aq) 2NaBr(aq) + H2O(l) + CO2(g)
net: Na2CO3(s) + 2H+(aq) 2Na+(aq) + H2O(l) + CO2(g)
-not redox; ion exchange where H2CO3 immediately decomposes to form H2O and CO2
-in net; you keep the Na+ because it is first in a solid and then in solution, the Br - is omitted because it is in solution on both sides of the yields arrow.
-Also driven by gas formation
- Br2(l) + 2NaI(aq) I2(s) + 2NaBr(aq)
-ox ½ rxn: 2I- I20 + 2e-
-red ½ rxn: Br20 + 2e- 2Br-
net: Br20 + 2I- I20 + 2Br-
-redox; nonmetal single replacement, iodide ion is oxidized to iodine, sodium iodide is the reducing agent. Liquid bromine is reduced and is thus the oxidizer or oxidizing agent.
- Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
-ox ½ rxn: Zn0 Zn2+ + 2e-
-red ½ rxn: 2H+ + 2e- H20
net: Zn0 + 2H+ Zn2+ + H20
-redox; metallic single replacement; zinc is oxidized to zinc(II) ion and is the reducing agent, hydrochloric acid is the oxidizing agent
- MgO(s) + HOH(l) Mg(OH)2(s)
net is the same as the overall equation because magnesium hydroxide is insoluble in water
not redox; combination, specifically metal oxide and water metal hydroxide or base
- SO2(g) + HOH(l) H2SO3(aq) which is in its net equation b/c sulfurous acid is a weak acid
However to if you had sulfur trioxide gas SO3(g) + HOH(l) H2SO4(aq) which would have
the following net: SO3(g) + HOH(l) 2H+2(aq) + SO42-(aq) In which the two molecular
reactants combine to form a strong acid, which immediately forms ions in the water
solution.
not redox; combination, specifically nonmetal oxide and water oxyacid
- HNO3(aq) + KC2H3O2(aq) KNO3(aq) + HC2H3O2(aq)
net: H+(aq)+ C2H3O2-1(aq) HC2H3O2(aq)
Ion exchange, two substances, which have only ions in solution, go over to form molecules of a weak acid in the product. Nitric acid (a strong acid) dissociates into ions in solution whereas acetic acid (a weak acid) does not dissociate significantly while in solution.
-Thus, the driving force is the formation of a weak acid
- NaH(s) + HOH(l) NaOH(aq) + H2(g)
-ox ½ rxn: 2NaH 2Na+ + H20 + 2e-
-red ½ rxn: 2HOH + 2e- H20 + 2OH-
net: NaH(s) + HOH(l) Na+(aq) + OH-(aq) + H2(g)
one reactant is a solid, the other is molecular, no ions in the reactants
redox: the hydrogen (+) ion in water is reduced, the hydride (-) ion in sodium hydride is oxidized. The original reaction is written in simplest form eliminating the 2 that is needed in the redox ½ reactions.
-Also driven by the formation of a gas.
- 2Na(s) + 2HOH(l) 2NaOH(aq) + H2(g)
-ox ½ rxn: 2Na0 2Na+ + 2e-
-red ½ rxn: 2H+ + 2e- H20
net: 2Na + 2HOH 2Na+ + 2OH- + H2
-redox; the sodium metal is oxidized and is the reducer, water is the oxidizer
-also driven by the formation of a gas
- Cu(s) + 2AgNO3(aq) Cu(NO3)2(aq) + 2Ag(s)
-ox ½ rxn: Cu0 Cu+2 + 2e-
-red ½ rxn: 2Ag+ + 2e- 2Ag0
net: Cu0 + 2Ag+ Cu2+ + 2Ag0
redox; metallic single replacement, the copper is oxidized by silver nitrate (which is the
oxidizing agent)