Presentation on theme: "The main tasks of Chap 8 Sect 1 - Writing reactions from word problems – challenging Sect 2 - Balance Equations—easiest Sect 3 - Classify Equations, Complete."— Presentation transcript:
1The main tasks of Chap 8Sect 1 - Writing reactions from word problems – challenging Sect 2 - Balance Equations—easiest Sect 3 - Classify Equations, Complete Equations—challenging Sect 4 – Write Net Ionic equations
2Classifying Reactions You will learn to recognize the different types of reactions ANDHow to complete products (predict).
3Combustion Reactions “Burning” Oxygen is a reactant.Energy is producedCombustion of carbon compounds yield carbon dioxide(CO2) and water (H2O ).Mg + O2 MgOCH4 + O2 CO2 + H2O
4Synthesis ReactionsTwo or more elements or compounds combine to form ONE PRODUCT.Mg + O2 MgOH O2 H2O
5Decomposition Reactions ONE REACTANT (compound) breaks into elements or smaller compounds.H2O H O2MgO Mg + O2
6Displacement Reactions Also called Replacement reactionsSingle Displacement/ReplacementUse the Activity seriesDouble Displacement/ReplacementPrecipitation ReactionsUse the Solubility RulesAcid Base Reactions
7Single DisplacementPart of an ionic compound is removed and replaced by a new element.ELEMENT + COMPOUND COMPOUND + ELEMENTThere are 2 subtypes of single replacement reactions.Cationic replacementAnionic replacement
8Single Displacement subtype CATIONIC REPLACEMENT: If the Element is a Metal, it replaces the metal in the compound.Cu AgNO3 Cu(NO3)2 + Ag
9Single Displacement subtype: ANIONIC REPLACEMENT: If the Element is a Non-metal, it replaces the non-metal in the compound.Cl NaBr NaCl Br2
10Single Replacement Rxns To determine if a Single Replacement Reaction really happens, use the ACTIVITY SERIES reference sheet.If an element is higher on the chart, it will become a compound.If the higher element is already in a compound, then NO reaction occurs
11Double Replacement Rxns Two Ionic Compounds that exchange partners.XY AB AY XBOnly Positive with NegativePositive Ion listed first
12Double Replacement Rxns To determine if the reaction occurs, use the SOLUBILITY RULES.A reaction occurs if a solid or water forms when two aqueous solutions of ionic compounds are mixed.If the products are both aqueous ionic compounds, then no reaction occurs.
13Solubility Rules info. Soluble = dissolves in water = (aq) = clear Insoluble= doesn’t dissolve in water = SOLID = (s) = cloudy = precipitate = ppt
14Section 4: Net Ionic Equations Three ways to write the same equation (usually with double replacement rxns):1. Complete Molecular Equation2. Complete Ionic Equation3. Net Ionic Equation
15Dissolving (aq) separates the ions NaCl (s) in water NaCl (aq)NaCl (aq) means Na+(aq) + Cl- (aq)The Ions move separately in solution.In some equations we separate the ions and write the charges.
16Complete Molecular Eqn This is what we have been doing. Write the compounds with the ions together.Example: NaCl (aq) + AgNO3 (aq)AgCl (s) + NaNO3(aq)
17Complete Ionic EqnsWrite the aqueous compounds as separate ions. Be sure to put the CHARGES ON THE IONS!Keep the solid(insoluble) or water molecules together.Example:Na+ (aq) + Cl- (aq) + Ag+(aq) + NO3- (aq) AgCl (s) + Na+(aq)+ NO3-(aq)
18Net Ionic EquationsTake the Complete ionic equation and remove any ion that is aqueous on both sides.These ions are called Spectator Ions.ORFind the Solid product or water, keep that part AND keep the reactant ions that made the solid or water.Ex: Ag+ (aq) + Cl- (aq) AgCl(s)
19Net Ionic Eqns with Acids and Bases( H+ and OH-) When acids (HA) and Bases (ZOH) mix, the H+ and OH- combine to become H2O(l). This is called a neutralization reaction. The water H2O(l) stays together like insoluble solids. So you keep it in the Net Ionic equation. Ex. H+ + OH- H2O
20Example: Complete and Net Ionic Equations page 1 Cu(NO3 )2 (aq) + NaOH(aq) ????1) Write Complete Molecular Equation:Cu(NO3 )2 (aq) + NaOH(aq) Cu(OH)2 (s) + NaNO3 (aq)2) Write Complete Ionic Equation: [separate all (aq), put charges on ions; keep solids together.]Cu+2(aq) +2NO3 -1(aq) + 2Na+1 (aq) + OH-1 (aq) Cu(OH)2 (s) + 2Na+1 (aq) + 2NO3 -1 (aq)And then…
21Example: Complete and Net Ionic Equations page 2 3) Write Net Ionic Equation: [eliminate spectator ions, keep ions that make solid, keep solids.] Cu+2(aq) + OH-1 (aq) Cu(OH)2 (s)