Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chemical Equations Preparation for College Chemistry

Similar presentations

Presentation on theme: "Chemical Equations Preparation for College Chemistry"— Presentation transcript:

1 Chemical Equations Preparation for College Chemistry
Columbia University Department of Chemistry

2 Chapter Outline The Chemical Equation Writing and Balancing Equations
Information in an Equation Types of Chemical Equations Heat in Chemical Equations The Greenhouse Effect

3 The Chemical Equation Al + Fe2O3 Fe + Al2O3 2 (s) (l)
Shorthand Expression for a Chemical Change Al Fe2O3 Reactants Fe Al2O3 Products 2 Stoichiometric Coefficients Conditions (s) (l) Physical State

4 Writing Chemical Equations
Identify the Reaction magnesium hydroxide + phosphoric acid magnesium phosphate + water Mg3(PO4) H2O Write the skeleton equation Mg(OH) H3PO4 Find the Stoichiometric Coefficients (Balance) 2 6 3 3Mg PO4 Mg R P 12 H 14 O 2

5 Types of Chemical Equations
Combination: A + B AB Decomposition AB A + B Single -Displacement A + BC AB + C Double -Displacement AB + CD AD + CB

6 Combination Reactions
metal + Oxygen metal oxide 2Mg(s) + O2(g) MgO(s) nonmetal + Oxygen non metal oxide 2S (s) + 3O2(g) SO3 (g) metal + nonmetal Salt 2Na (s) + Cl2(g) NaCl(s) metal oxide + water Metal Hydroxide MgO (s) + H2O(l) Mg(OH)2(s) nonmetal oxide + water Oxy-acid SO3 (g) + H2O(g) H2SO4(s)

7 Decomposition Reactions
Metal oxides 2HgO(s) Hg (l) + O2(g) 2PbO2(g) PbO (g) + O2(g) Carbonates and Hydrogen carbonates CaCO3 (s) CaO (s) + CO2(g) 2NaHCO3 (s) Na2CO3 (s) + H2O(l) + CO2(g) Other decomposition reactions 2KClO3 (s) 2KCl (s) + 3O2(g) 2NaNO3 (s) 2NaNO2 (s) + O2(g) 2H2O2 (l) 2H2O (l) + O2(g) 2NaN3 (s) 2Na (s) + 3N2(g)

8 Single-Displacement Reactions
metal + acid Hydrogen + Salt Zn(s) + 2HCl(g) H2(g) ZnCl2(s) metal + water Hydrogen + metal hydroxide or oxide 2Na(s) + 2H2O(l) H2(g) NaOH(aq) metal + Salt Salt + metal Zn(s) + CuSO4(aq) ZnSO4(aq) + Cu(s) halogen + halide salt Halide salt + Halogen Cl2 (g) + 2NaBr(aq) NaCl(aq) + Br2(l)

9 Double-Displacement Reactions
AB + CD AD + CB NaCl(aq) + KNO3(aq) NaNO3(aq) + KCl(aq) Physical Evidences for double-displacement Formation of an Insoluble precipitate Evolution of Heat (Neutralization Reactions) Gas Formation

10 Precipitation Reactions
Appendix V Solubility Table NO3- All nitrates are soluble Cl- AgCl, Hg2Cl2, PbCl2 All chlorides are soluble, except SO42- Most sulfates are soluble, except SrSO4, PbSO4 and BaSO4 CaSO4 is slightly soluble CO32- All carbonates are insoluble, except Group I and NH4+ OH- All hydroxides are insoluble, except group I Sr(OH) 2 and Ba(OH)2. Ca(OH) 2 is slightly soluble S2- All sulfides except Groups I and II and NH4+ are insoluble

11 Solubility Rules Used to predict results of precipitation reactions
Example 1 What happens when solutions of Ba(NO3)2 and Na2CO3 are mixed? Ions present: Ba2+ (aq), NO3-(aq), Na+(aq), CO32-(aq) Possible precipitates: BaCO3, NaNO3 According to solubility rules, BaCO3 is insoluble Ba2+(aq) + CO32-(aq) BaCO3(s)

12 Solubility Rules Example 2 Mix solutions of BaCl2, NaOH
ions present: Ba2+(aq) , Cl-(aq), Na+(aq), OH-(aq) possible precipitates: Ba(OH)2, NaCl both are soluble; no reaction

13 Net Ionic Equations (Spectator ions do not appear)
Example Mix solutions of Cu(NO3)2, NaOH ions present: Cu2+(aq), NO3 -(aq), Na+(aq), OH-(aq) possible precipitates: Cu(OH)2, NaNO3 NaNO3 is soluble; Cu(OH)2 is not. Spectator ions: Na+(aq), NO3 -(aq) Net Ionic Equation: Cu2+ (aq) + 2 OH- (aq) Cu(OH)2 (s)

14 Heat in Chemical Reactions
Endothermic Reaction Potential Energy Activation Energy Products Net Energy absorbed Reactants Time

15 Heat in Chemical Reactions
Exothermic Reaction Potential Energy Activation Energy Reactants Net Energy released Products Time


Download ppt "Chemical Equations Preparation for College Chemistry"

Similar presentations

Ads by Google