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Chapter 5 A Closer Look at Chemical Equations. Single Replacement Equations Decomposition Gas-Forming Reactions Neutralization Reactions Precipitation Reactions Oxidation-Reduction Reactions. Single Replacement Reactions.
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Chapter 5A Closer Look at Chemical Equations Single Replacement Equations Decomposition Gas-Forming Reactions Neutralization Reactions Precipitation Reactions Oxidation-Reduction Reactions
Single Replacement Reactions • Single replacement reactions are reactions that involve an element replacing one part of a compound • The products include the displacement element and a new compound. • An element can only replace another element that is less active than itself. hfinks '07
General Activity Series for Metals • Li (most active) • Ca • Na • Mg • Al • Zn • Fe • Pb • [H2] • Cu • Ag • Pt (least active) hfinks '07
Can metal 1 replace metal 2? hfinks '07
General Activity Series for Nonmetals • F2 (most active) • Cl2 • Br2 • I2 (least active hfinks '07
Can nonmetal 1 replace nonmetal 2? hfinks '07
Active metals replace less active metals from their compounds in aqueous solutions. • Example: Magnesium turnings are added to a solution of iron (III) chloride. 3 Mg(s) + 2FeCl3 --- > 3 MgCl2 + 2 Fe(s) hfinks '07
Can metal 1 replace metal 2 in compound? hfinks '07
Active metals replace hydrogen in water • Example: Sodium is added to water. 2Na(s) + 2 HOH --- > 2NaOH(aq) + H2(g) hfinks '07
List the products hfinks '07
Active metals replace hydrogen in acids. • Example: Lithium is added to hydrochloric acid • 2 Li(s) + 2HCl(aq) --- > H2(g) 2 LiCl(aq) hfinks '07
List the products hfinks '07
Are these reactions possible? hfinks '07
Active nonmetals replace less active nonmetals from their compounds in aqueous solutions. • Example: Chlorine gas is bubbled into a solution of potassium iodide • Cl2(g) + 2 KI(aq) --- > I2(g) + 2 KCl(aq) hfinks '07
If a less reactive element is combined with a more reactive element in compound form, there will be no resulting reaction. • Example: Chlorine gas is bubbled into a solution of potassium fluoride • Cl2(g) + KF(aq) --- > No reaction hfinks '07
Are these reactions possible? hfinks '07
1. Cu(s) + H2O(l) --- > No reaction • 2. Br2(l) + 2NaI(s) --- > I2(g) + 2NaBr • 3. Al(s) + 3AgNO3(aq) --- > Al(NO3)3 + 3Ag • 4. Zn(s) + H2SO4(aq) ---- > ZnSO4 + H2(g) hfinks '07
3F2(g) + 2AlCl3(aq) --- > 3Cl2(g) + 2AlF3 • Mg(s) + Pb(C2H3O2)2(aq) -- > Mg(C2H3O2)2 + Pb(s) • I2(g) + NaCl(aq) --- > No reaction • Ca(s) _+ 2HNO2 ---- > Ca(NO2)2 + H2 hfinks '07
2Li(s) + 2 H2O(l) ---- > 2LiOH + H2(g) • FeCl3(aq) + Pt(s) ---- > No reaction hfinks '07
P.Q. I – Activity Series • Which is the more active metal? Ca or Ag • Which is the more active nonmetal? Cl2 or Br2 • Which reaction isn’t possible? a. 2Na + Cl2 ---- > 2 NaCl b. KBr + F2 ---- > 2KF + Br2 c. Cu + HCl ---- > CuCl2 + H2 hfinks '07
Decomposition reactions occur when a single reactant is broken down into two or more products. hfinks '07
Metallic Carbonates • Decompose into metallic oxides and carbon dioxide • Example: A sample of magnesium carbonate is heated. • MgCO3 --- > MgO + CO2 hfinks '07
Metallic Carbonates hfinks '07
Metallic chlorates decompose into metallic chlorides and oxygen. Example. A sample of magnesium chlorate is heated. Mg(ClO3)2(s) --- > MgCl2(s) + 3 O2(g) hfinks '07
Ammonium carbonate decomposes into ammonia, water and carbon dioxide. (NH4)2CO3--- >2 NH3(g) + H2O(l) + CO2(g) hfinks '07
Sulfurous acid decomposes into sulfer dioxide and water. H2SO3 ---- > H2O + SO2(g) hfinks '07
Carbonic acid decomposes into carbon dioxide and water. H2CO3 ---- > H2O + CO2(g) hfinks '07
A binary compound may break down to produce two elements. 2 NaCl ---- > 2 Na + Cl2 hfinks '07
Hydrogen peroxide decomposes into water and oxygen. 2H2O2 --- > 2 H2O + O2 hfinks '07
Ammonium hydroxide decomposes into ammonia and water. NH4OH --- > NH3 + HOH hfinks '07
Synthesis reactions occur when two or more reactants combine to form a single product. hfinks '07
A metal combines with a nonmetal to form a binary salt. Example: solid sodium oxide is added to water 6 Li(s) + N2(g) --- > 2Li3N(aq) hfinks '07
Type 2 Metallic oxides and water form bases (metallic hydroxides). Solid sodium oxide is added to water Na2O(s) + HOH(l) --- > 2 NaOH(aq) hfinks '07
Type 3 Nonmetallic oxides and water form acids. The nonmetal retains its oxidation number. Example: Carbon dioxide is bubbled into water CO2(g) + H2O(l) ---- > H2CO3(aq) hfinks '07
Type 4. Metallic oxides and nonmetallic oxides form salts. Example: Solid sodium oxide is added to carbon dioxide Na2O(s) + CO2(g) ---- > Na2CO3(s) hfinks '07
CaCO3(s) --- > CaO(s) + CO2(g) • SO2(g) + H2O(l) -- > H2SO3(aq) • K2O(s) + CO2(aq) --- > K2CO3 • 2H2O2(l) ---- > 2H2O(l) + O2(g) hfinks '07
5. Li2O(s) + HOH(l) --- > 2 LiOH(aq) 6. 2AlCl3(l) --- > 2 Al(l) + 3 Cl2(g) 7. 2Na(s) + I2(g) --- > 2NaI(s) 8. H2CO3 (aq) --- > CO2(g) + H2O(l) hfinks '07
2KClO3(s) --- > 2KCl(s) + 3 O2(g) • MgO(s) + SO3(g) --- > MgSO4(s) hfinks '07
Double Replacement Reactions Formation of a Gas Neutralization Reactions Formation of a Precipitate
Formation of A Gas Common Gases in Metathesis Reactions
Gas 1. H2S Any sulfide (salt of S2-) plus any acid form H2S(g) and a salt. Example: iron (II) sulfide + hydrochloric acid FeS(s) + 2HCl(aq) -- > FeCl2(aq) + H2S(g) hfinks '07
Gas 2. Carbon Dioxide Any carbonate salt (salt of CO32-) plus any acid form CO2(g) , H2Oand a salt. Example: Potassium carbonate plus nitric acid K2CO3(s) + 2 HNO3(aq) -- > CO2(g) + HOH(l) + 2KNO3(aq) hfinks '07
Gas 3. SO2 Any sulfite (salt of SO32-) plus any acid form SO2(g), HOH and a salt Example: sodium sulfite plus hydrochloric acid Na2SO3(s) + 2HCl(aq) --- > 2NaCl(aq) + SO2(g) + HOH(l) hfinks '07
Gas 4. NH3 Any ammonium salt (salt of NH4+) plus any soluble strong hydroxide react upon heating to form NH3(g), HOH and a salt. Example: ammonium chloride plus sodium hydroxide NH4Cl(aq) + NaOH -- > NH3(g) + HOH(l)+ NaCl(aq) hfinks '07