1. Chemical Equations and Reactions

2. Chemical Equations Law of Conservation of Matter Law of Mass Balance
Matter is neither created nor destroyed, only changed in form.
Law of Mass Balance
For any given chemical change:
Σ Mass Reactants = Σ Mass Products

3. Chemical Equations Types of Chemical Equations Molecular Equations
3H2(g) + N2(g) NH3(g)
Mg(s) + O2(g) MgO(s)
2KClO3(s) + Heat KCl(s) + 3O2(g)
Pb(NO3)2(aq) + 2NaI(aq) NaNO3(aq) + PbI2(s)

4. HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)
Chemical Equations
Types of Chemical Equations
Molecular Equation
HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)
Ionic Equations
H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) Na+(aq) + Cl-(aq) + H2O(l)
Net Ionic Equations
H+(aq) + OH-(aq) H2O(l)

5. Chemical Equations Thermochemical Equations
The Exothermic Reaction Eqations
N2(g) + 3H2(g) NH3(g); ΔHRxn = Kj
N2(g) + 3H2(g) NH3(g) Kj
The Endothermic Reaction Equations
H2O(l) H2O(g); ΔHRxn = 44 Kj
H2O(l) + 44 Kj H2O(g)

6. Chemical Equations Ionization Equations Oxidation (loss of electrons)
Nao(g) Na+(g) + e-
[e- on product side of equation indicates ‘loss’ of electron by oxidation]
Reduction (gain of electrons)
Clo(g) + e Cl-(g)
[e- on reactant side of equation indicates ‘gain’ of electron by reduction]

7. Chemical Equations Word Equations
magnesium + nitrogen gas → magnesium nitride
hydrogen + bromine → hydrogen bromide
sodium oxide _ethyne + oxygen → carbon dioxide + water
acetic acid + calcium carbonate → calcium acetate + water + carbon dioxide
aluminum + iron(III) oxide → iron + aluminum oxide
aluminum + copper(II) chloride → copper + aluminum chloride
copper(II) chloride + sodium carbonate → sodium chloride + copper(II) carbonate

8. Chemical Equations Classification of Chemical Reactions
Oxidation/Reduction Reactions
Composition A + B AB
Decomposition AB A + B
Single Replacement A + BX AX + N
Metathesis Reactions
Double Replacement AX + BY AY + BX
Combustion Reactions
Hydrocarbons + O2(g) CO2(g) + H2O(g)

9. Chemical Equations Decomposition – Composition Reactions AB A + B
(Number Product Compounds > no. Reactant Compounds)
A + B AB
(Number Product Compounds < no. Reactant Compounds)
In general, composition reactions are simply decomposition reactions in reverse.

10. Chemical Equations Decomposition/Compostion Reactions
Chlorates >>>> Salt + Oxygen
Oxides of Metals >>> Metal + Oxygen
Acids (Weak Oxoacids) >>> Nonmetal Oxide + HOH
Carbonates, Sulfates & Nitrates >>> Nonmetal Oxide + Metal Oxide
Hydroxides >>> Metal Oxide + HOH
Electrolytic Decomposition >>> Basic Elements in Standard State

11. Chemical Equations Predict the products of the following:
KClO3(s) + Heat >>> ?
Fe2O3(s) + Heat >>> ?
H2CO3(aq) + Heat >>> ?
CaCO3(aq) + Heat >>> ?
Ca(OH)2(aq) + Heat >>> ?
NaBr(aq) + Electricty >>> ?

12. Chemical Equations Single Replacement Reactions (1o Reactions)
A + BX AX + B
Driving force in the single replacement reaction is the replacement of a metalli with a more active metallic element.
Replacement follows activity as listed on the ‘Activiy Series’.

13. Chemical Equations The Activity Series
Metal
Ion
Reactivity
Extraction Cs
Cs+
reacts with water
electrolysis Rb
Rb+ K K+ Na
Na+ Li
Li+ Ra
Ra2+ Ba
Ba2+ Sr
Sr2+ Ca
Ca2+ Mg
Mg2+
reacts with acids Al
Al3+ Ti
Ti4+
reacts with concentrated mineral acids
Pyrometallurgical extraction using magnesium, or less commonly other alkali metals, hydrogen or calcium in the Kroll process Mn
Mn2+
smelting with coke Zn
Zn2+ Cr
Cr3+ Fe
Fe2+ Cd
Cd2+ Co
Co2+ Ni
Ni2+ Sn
Sn2+ Pb
Pb2+ Sb
Sb3+
may react with some strong oxidizing acids
heat or physical extraction Bi
Bi3+ Cu
Cu2+ W
W3+ Hg
Hg2+ Ag
Ag+ Pt
Pt2+ Au
Au3+

14. Chemical Equations The Activity Series and 1o Reactions
Predict the products of the following:
Mgo(s) + CuCl2(aq) (?)
Zno(s) + AgNO3(aq) (?)
Pbo(s) + CaI2(aq) (?)
Sno(s) + AlCl3(aq) (?)

15. Chemical Equations Oxidation & Reduction Process in Single Replacement Reactions
Oxidation Process ≡ The transfer (loss) of e-’s during chemical reaction process to form Cations.
Metal (Cation)+ + e-
Lio (g) Li+(g) + e-
Cao(g) Ca2+(g) + 2e-
Alo(g) Al3+(g) + 3e-

16. Chemical Equations Oxidation & Reduction Process in Single Replacement Reactions
Reduction Process ≡ The gain of e-’s into the atomic valence level during chemical reaction process.
Nonmetal* + e (Anion)-
Po(g) + 3e P3-(g)
So(g) + 2e S2-(g)
Bro(g) + e Br-(g)
*NOTE: Typically, nonmetal elements are used to illustrate the formation of anions through the reduction process. However, keep in mind that metallic ‘Main Group Elements’ are subject to gaining electrons and functioning as anions also, especially the metalloid elements.

18. Oxidizing Agents and Reducing Agents:
Oxidizing Agents ≡ Substances that cause another substance to undergo oxidation.
Reducing Agents ≡ Substances that cause another substance to undergo reduction.
Zno(s) Zn+2(aq) + 2e- is an oxidation process, but Zinc is a reducing agent.
Cu+2(aq) + 2e Cuo(s) is a reduction process, but Copper(II) is an oxidizing agent.
Reducing Agent
Oxidizing Agent

19. Chemical Equations The Double Replacement Reactions and The Metathesis Process
The Double Replacement Reaction ( 2o Rxn )
AX + BY AY + BX
Characteristics
Ionic Exchange Reaction.
Oxidation states do NOT change during process.
Driving force of reaction is the tendency to form a more stable product substance; i.e., solid ppt, liquid wk electrolyte, or gas decomposition product. (The ‘Driving Force’ prevents the reaction from reversing during process.)

20. 2NaCl(aq) + Pb(NO3)2(aq) 2NaNO3(aq) + [ PbCI2(s) ]
A+ X B+ Y A+ Y (BX)
IONIC
DRIVING FORCE
2NaCl(aq) Pb(NO3)2(aq) 2NaNO3(aq) [ PbCI2(s) ]
2[1(+)+1(-)]
[1(+2)+2(-1)]
2[(+1)+(-1)]
[1(+2)+2(-1)]
Driving Force Compound – Is not shown in ionic form.

21. Chemical Equations Equations from Metathesis Rxns
Molecular Equation: Ionic Equation: Net Ionic Equation:
2NaCl(aq) Pb(NO3)2(aq) NaNO3(aq) PbCI2(s)
2Na+ (aq) + 2Cl- (aq) + Pb+2(aq) + 2NO3- (aq) Na+ (aq) + 2NO3- (aq) + PbCI2(s)
2Na+ (aq) + 2Cl- (aq) + Pb+2(aq) + 2NO3- (aq) Na+ (aq) + 2NO3- (aq) + PbCI2(s)
Spectator Ions
Pb+2(aq) + 2Cl-(aq) PbCI2(s)
Typically, the cation (metal) is listed first & followed by the anion (nonmetal).
The ‘driving force’ products are NOT shown in Ionic form.

22. Sodium Phosphate + Calcium Nitrate >>>> ?
Predict the products resulting from mixing the following ionic compounds. Write and balance
The molecular equation
The ionic equation
The net ionic equation
Sodium Phosphate + Calcium Nitrate >>>> ?