Don’t forget to look up your advisorDon t forget to look up your advisorhttp://www.forwolves.org/ralph/wolfrpt.htmlReactions—continuedAnd chemical review!!And chemical review!!Atomic vs Molecular WeightAtomic vs. Molecular Weight• Atomic weight on periodic table is average of natural abundance of isotopesp• Atomic mass is the number of nucleons in a particular atomspecified by isotopea particular atom—specified by isotope• Molecular mass is the mass of one mole of molecules–One atomic mass number of gramsOne atomic mass number of grams– 6.0221367x1023moleculesCalculate Molecular MassCalculate Molecular Mass• O atomic weight 15.9996 (round to 16 for this class))• O-16 atomic mass 16 uMl l Oti 32•Molecular oxygen O2 atomic mass 32 u•Molecular O2molecular mass 32 g/moleoecua O2o ecu a ass 3 g/ o e•CO2molecular massC12 / l O32 / lC=12 g/mole, O2=32 g/mole CO2=12+32=44 g/moleGrams calculated from MolesGrams calculated from Moles• Find the molar mass of substance Na=231moleg mole of Na • Multiply molar mass times moles41molepy• 23 x 0.250 moles = 5.75 gmolegMoles calculated from GramsMoles calculated from Grams• 176 g of CO2 = Number of moles?• Molar mass of CO2= 44 moleg2 • If you multiply, 176 g x 44 results in units oflgg2mole176 g x 44 results in units of you get a unit messUNITSalert you that you made an errormolemoleUNITSalert you that you made an error KEEP UNITS WITH NUMBERS!!Moles calculated from GramsMoles calculated from Grams• 176 g of CO2 = Number of moles?• Molar mass of CO2= 44 moleg2 • Divide 176 g by 44•Same as multiply by reciprocalmoleg•Same as multiply by reciprocal(1mole)176 g x (1 mole44 g)= 4 moles CO2• Now the grams cancel =)Mass to moles relationshipMass to moles relationshipTo convert between grams and molesTo convert between grams and moles• Know the formula mass of the molecule•Multiply moles times grams/mole to getMultiply moles times grams/mole to get gramsDi id b / l t t l•Divide grams by grams/mole to get molesTo find grams of reactant or productTo find grams of reactant or product• Make sure equation is balanced•So you know the molar ratios of themSo you know the molar ratios of them• Use molar mass of them• Proceed as required–Divide grams by grams/mole to know molesDivide grams by grams/mole to know moles– Determine moles of unknownMltil itb / l t fid–Multiply it by grams/mole to find gramsProblemNOONOProblem22NOONO• 64 grams O2• How many grams NO2produced?yg2pFirst: Balance Equation22NOONO2222NOONOProblem2222NOONOProblem2222NOONO• 64 grams O2• How many grams NO2produced?yg2pBalance EquationDetermine molar ratios of them 1:2Determine molar ratios of them 1:2Find formula mass of each component NO46 O32 (NO 30 )NO2=46 g, O2=32 g, (NO=30 g)Problem2222NOONOProblem2222NOONO• 64 grams O2• How many grams NO2produced?yg2pFormula mass of each: O2=32 g, NO2=46 g How many moles is 64 grams O2?How many moles is 64 grams O2?One moleProblem2222NOONOProblem2222NOONO• 64 grams O2• How many grams NO2produced?yg2p• Formula mass of each O2=32 g, NO2=46 gMolar ratios O2:NO2 is 1:2TwomoleofOTwo mole of O2So four moles of NO2 is producedHow many grams is that?4molx46g/mol=184 grams4 mol x 46 g/mol 184 gramsProblemProblemOHSOOSHOHSOOSH2222• 32 grams SO2•How many grams O2used?How many grams O2used?Problem• 32 grams SO2•How many grams Oused?ProblemOHSOOSH•How many grams O2used?•Balance firstOHSOOSH2222Balance firstOHSOOSH22222232•Then determine molar ratiosOHSOOSH22222232Then determine molar ratios•2 SO2 to 3 O2Problem• 32 grams SO2•How many grams Oused?ProblemOHSOOSH2232•How many grams O2used?OHSOOSH22222232• Find molar masses SO2= 32 + 32 = 64 g/mol SO2 O2 = (2x1) +16 = 32 g/mol O2HO= (2x1) +16=18 g/mol HOH2O= (2x1) +16 =18 g/mol H2O H2S= (2x1) +32 = 34 g/mol H2S 2()g2Problem• 32 grams SO2•How many grams Oused?ob eOHSOOSH2232•How many grams O2used?OHSOOSH22222232•32 g SOneeds how many grams O?•32 g SO2needs how many grams O2?• How many moles is 32 g SO2?SO50 1SOg32molesmole22SO 5.0g 64SO g 32molesProblem• 32 grams SO2•How many grams Oused?ProblemOHSOOSH2232•How many grams O2used?OHSOOSH22222232•How many moles Ois needed?•How many moles O2 is needed?•0.5 moles SO2in 2:3 ratio with O2• 0.75 moles O222SO5.0 1SO g 32 molesmole22g64gProblemCOOCProblem22COOCIs it balanced?Molar ratio 1:1:1 4 grams oxygenGrams carbon consumed?Grams carbon consumed? Grams carbon dioxide produced?ProblemCOOCProblem22COOCMolar ratio 1:1:1 4 grams oxygen• 1 mole O2= 32 g22125.01 4 OmolesmoleOg2232ggProblemCOOCProblem22COOCMolar ratio 1:1:1 0.125 moles O2in 1:1 ratio0.125 moles C0 125 l CO0.125 moles CO2Problem 6COOCProblem 622COOC0.125 moles CGrams carbon consumed?CggCmoles51121250CgmoleCmoles5.1 1125.0225.544mole 125.0 COggCO 221gmoleReaction SpeedReaction SpeedCollision of molecules required for it to occur•Increase concentrationIncrease concentration• Increase temperature• Catalyst can facilitate reactionChlorine catalystChlorine catalystEnergy of reactionsEnergy of reactions• Release energy•EXOTHERMICEXOTHERMIC• Methane combustion•Consume energy•Consume energy• ENDOTHERMIC• Formation of
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