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Chapter 3A & 4AStoichiometry and ReactionsChemical ReactionsChemical equation a representation of a chemical reaction.

Reactants the starting chemicals.

Products the ending chemicals.

CH4 + O2 CO2 + H2O Reactant Product

Conservation of matter in a chemical reaction, atoms are neither created nor destroyed.

Physical StatesThe state of the compound can be stated in the reaction equation using the following symbols.

Solid (s)Liquid (l)Gas (g)Dissolved in water (aq)

Balancing Equations C(s) + O2(g) CO2(g) Reactants Products

All atoms present in the reactants must be accounted for among the products

C-1 C-1 O-2 O-2

Balancing RulesRead the description and write the formulas for the reactants and products.

Write the unbalanced formula.

Balance the equation starting with the most complicated molecule. Remember to not change the formula of the chemicals.

Check to confirm balance.

Balancing EquaitonsMethane reacts with oxygen to produce carbon dioxide and water.

CH4(g) + O2(g) CO2(g) + H2O(l)

C-1 C-1 H-4H-2 O-2O-3

Balancing equationsK + H2O H2 + KOH

NH3 + O2 NO + H20

SiO2 + HF SiF4 + H2O

CaC2 + H2O Ca(OH)2 + C2H2

Balancing EquationsHydrogen gas combines with oxygen gas to produce water.

Sodium metal combines with water to produce sodium hydroxide liquid and hydrogen gas.

Aluminum solid combines with chlorine gas to produce aluminum chloride solid.

Hydrochloric acid (aqueous solution) combines with calcium carbonate solid to form calcium chloride, carbon dioxide gas and water.

Reaction TypesComposition (synthesis)DecompositionSingle ReplacementDouble replacement (precipitation)Acid/Base

Reaction TypesComposition reaction a reaction that combines substances to form a single substance.A + B C

2H2 + O2 2H2OC + O2 CO22Na + Cl2 2NaCl

Reaction TypesDecomposition reaction a reaction in which a compound is broken down into two or more simpler substances.AB A + B

2H2O 2H2 + O22NaCl 2Na + 2ClCaCO3 CaO + CO2

Reaction TypesSingle replacement reaction a reaction in which one element takes the place of another elementA + BC B + AC

Cu + 2AgNO3 Cu(NO3)2 + Ag2K + 2H2O H2 + 2KOH

Reaction TypesDouble replacement reaction a reaction in which two different compounds exchange positive ions and form two new compounds.AB + CD AD + CB

Pb(NO3)2 + KI PbI2 + 2KNO3CaCO3 + 2HCl CaCl2 + H2CO3

Reaction Types2K + Cl2 2KCl

Fe2O3 + 2Al Al2O3 + 2Fe

2Mg + O2 2MgO

HNO3 + NaOH H2O + NaNO3

KBr + AgNO3 AgBr + KNO3

PbO2 Pb + O2Single Replacement ReactionIf the free metal is higher on the metal activity table than a metal in solution then the free metal will exchange places with the metal in solution.

Ex. Zn + HBr NiCl2 + K Cu + HCl Double Replacement Reaction PredictionMetathesis reactions are driven by three "driving forces."1) A product is a precipitate2) A product is a gas3) A product is a weak or non-electrolyte We reduced these to;1) A product is an ionic precipitate2) A product is a molecular, non-strong acid

Double ReplacementThe solubility table is used to determine if an ionic precipitate is formed from the reactants.

Ex. K2S + Fe(NO3)2Na2SO4 + BaCl2HCl + MgS KI + NH4NO3Double Replacement ReactionMolecular equation equation in which the complete formulas of all reactants and products are given.

Complete ionic equation equation in which all substances that are strong electrolytes are represented as ions.

Spectator ions ions which do not participate in the reaction.

Net ionic equation equation in which the spectator ions are not represented only the components involved in the reaction.Double Replacement ReactionFor each of the following reactions, write the balanced molecular equation, the balanced complete ionic equation, and the balanced net ionic equation.

Silver nitrate and sodium chromateAgNO3 + NaCrO4Nickel(II) nitrate and potassium carbonateNi(NO3)2 + K2CO3ElectrolytesStrong Electrolytes ionic compounds that total dissociate in water and conduct electricity.

Weak electrolytes molecular acids that can totally or partially dissociate in water.

Non electrolytes molecular compounds that do not dissociate in water so do not conduct electricity.

Acid/Base ReactionsAcids substances that ionize in aqueous solutions to form hydrogen ions.

H2SO4(aq) H+(aq) + HSO4-(aq)

Strong acids strong electrolytes

Bases substances that ionize in aqueous solutions to form hydroxide ions.

NaOH(s) Na+(aq) + OH-(aq)

Strong Acids/BasesStrong AcidsHCl hydrochloric acidHBr hydrobromic acidHI hydroiodic acidHClO3 chloric acidHClO4 prechloric acidHNO3 nitric acidH2SO4 sulfuric acid

Strong BasesGroup 1A metal hydroxides (LiOH, NaOH, KOH, RbOH, CsOH)Group 2a metal hydroxides (Ca(OH)2, Sr(OH)2, Ba(OH)2)Acid/Base ReactionsAcid/Base reactions result in the formation of a salt and water

Ex. Write the balanced molecular, balanced complete ionic, and balanced net ionic equations for the reaction of aqueous hydrobromic acid and aqueous sodium hydroxide.

Acid/Base ReactionWrite the balanced molecular, balanced complete ionic, and balanced net ionic equations for the reaction of aqueous sulfuric acid and aqueous potassium hydroxide.