Transcription
Steps to Predicting theProducts of ChemicalReactionsCP Chemistry
TYPES OF REACTIONS REVIEW 2 NaNO3 PbO Pb(NO3)2 Na2ODouble Displacement C2H4O2 2 O2 2 CO2 2 H2OCombustion ZnSO4 Li2CO3 ZnCO3 Li2SO4Double Displacement V2O5 5 CaS 5 CaO V2S5DOuble Displacement S8 8 O2 8 SO2Synthesis
Organize Your ThoughtsChemicalreactionsChemicalequations Synthesis Decomposition Single replacement Double replacement CombustionPackard, Jacobs, Marshall, Chemistry Pearson AGS Globe, page 175Chemicalequations Balancing equations Predicting productsfrom reactants
PREDICTING THE PRODUCTS We want to be able to predict theproducts for the following reactiontypes Combustion Single Displacement Double Displacement
RULES FOR PREDICTING PRODUCTSOF CHEMICAL REACTIONS Here are a few important things toremember when predicting products: The compounds form must be neutralionic compounds (which means you’ll bepaying attention to their charges) You do NOT carry subscripts from thereactants to the products. You always balance your equation LAST
PREDICTING REACTION PRODUCTS:COMBUSTION REACTIONS A hydrocarbon and oxygen (O2) indicate acombustion reaction If it is combustion, then just write H2O andCO2 as products Then, balance the equation (can be tricky) Examples:2 H2O2 2 CO2 CH4 O2 C4H10 10 H2O13 O2 à 8 CO2
PREDICTING REACTION PRODUCTS:REPLACEMENT REACTIONS A metal will not alwaysreplace a metal in acompound dissolved inwater because of differingreactivities An activity series can beused to predict if reactionswill occur To replace a metal, theother metal must be MOREREACTIVE Same applies for halogens
PREDICTING REACTION PRODUCTS:SINGLE REPLACEMENT REACTIONS To predict the products: Replace the singleelement with the corresponding element inthe compound A metal will replace the cation in the compound A non-metal will replace the anion in thecompound If the element is more reactive than the oneit attempts to replace, then the reaction willbe spontaneous and exothermic Otherwise, it will not be spontaneous and willbe endothermic (NO REACTION)
PREDICT IF THESE REACTIONS WILL OCCUR3 Mg 2 AlCl32 Al 3 MgCl2Can magnesium replace aluminum?Activity SeriesAl MgCl2YES, magnesium is more reactive than aluminum.No reactionCan aluminum replace magnesium? NO, aluminum is less reactive than magnesium.Therefore, no reaction will occur.Activity SeriesMgCl2 AlNo reactionOrder of reactantsDOES NOTdetermine howthey react.The question we must ask is can the single element replace its counterpart?metal replaces metal or nonmetal replaces nonmetal.
PREDICTING REACTION PRODUCTS:SINGLE REPLACEMENT REACTIONSActivity SeriesFe CuCl2Can Fe replace Cu?Zn FeCl2MgCl2 Br2Can Br replace Cl?CuYesZn(NO3)2HNO3Can Zn replace H? H2YesNO REACTIONMgBr2 2Br2I2
PREDICTING REACTION PRODUCTS:DOUBLE REPLACEMENT REACTIONS If it is double replacement, then the cationand anions switch places It is helpful to separate each compoundinto their cation and anionic parts with theircharges Then switch places, and criss cross the newcompounds to make sure they are thecorrect neutral compound formulas
PREDICTING REACTION PRODUCTS:DOUBLE REPLACEMENT REACTIONS AB and CD are both ionic compounds Separate each compound & write theircharges Switch places and re-write new compounds Example: Pb(NO3)2 2 KI PbI2 2 KNO3Pb2 NO3K IPb2 IK NO3 Balance at the end!!
PREDICTING REACTION PRODUCTS:DOUBLE REPLACEMENT REACTIONS Not all double replacement reactions will occur In order for a double replacement reaction totake place: Both of the reactants must be soluble in water If a compound contains at least one of the ionsthat is proven soluble, then the compound will beat least moderately soluble One product must be soluble and oneproduct must be insoluble The insoluble product is the precipitate thatforms when the reaction takes place Usually a precipitate is a solid, but it doesn'thave to be
SOLUBILITY TABLE
PREDICTING REACTION PRODUCTS:DOUBLE REPLACEMENT REACTIONSPredict if a reaction will occur when you combine aqueous solutionsof iron (II) chloride with aqueous sodium carbonate solution.If the reaction does occur, write a balanced chemical equation showing it.iron (II) chloride sodium carbonateFeCl2 (aq) Na2CO3(aq)Using a SOLUBILITY TABLE:Both reactants are solubleSO REACTION OCCURS!?2 NaCl (aq) FeCO3(ppt)Using a SOLUBILITY TABLE:sodium chloride is solubleiron (II) carbonate isinsoluble so reactionoccurs!!
TYPES OF REACTIONS REVIEW ! 2 NaNO 3 PbO Pb(NO 3) 2 Na 2O C 2H 4O 2 2 O 2 2 CO 2 2 H 2O ZnSO 4 Li 2CO 3 ZnCO 3 Li 2SO 4 ! V 2O 5 5 CaS 5 CaO V 2S 5 ! S 8 8 O 2 8 SO 2 Double Displacement Combustion Double Displacement DOuble Displacement
