17
Stoichiometry Stoichiometry
StoichiometryStoichiometry
ProblemProblem
• If 16.8g of CO is mixed under high If 16.8g of CO is mixed under high pressure with 1.78g of Hpressure with 1.78g of H22. What is . What is the mass of ethanol (CHthe mass of ethanol (CH33OH)OH) will be will be produced?produced?
What do you do first?What do you do first?
• Balance the equationBalance the equation
• CO g to methanol molesCO g to methanol moles
• HH22 g to methanol moles g to methanol moles
CORRECT!CORRECT!
• CO+HCO+H22 CH CH33OHOH
• Which equation balances the reaction?Which equation balances the reaction?
CO+2HCO+2H2 2 2CH 2CH33OHOH
CO+2HCO+2H2 2 CHCH33OHOH
3CO+3H3CO+3H22 2CH 2CH33OHOH
INCORRECT!INCORRECT!
• Remember that you need to have Remember that you need to have both sides of the reaction equal both sides of the reaction equal before you can make an equationbefore you can make an equation
Try AgainTry Again
CORRECTCORRECT
• CO+2HCO+2H2 2 CHCH33OHOH
• What is next?What is next?
Convert everything to molesConvert everything to moles
Convert everything to gramsConvert everything to grams
• leave everything as it isleave everything as it is
INCORRECTINCORRECT
TRY AGAINTRY AGAIN
INCORRECT!INCORRECT!
• Remember that you need to have Remember that you need to have both sides of the reaction equal both sides of the reaction equal before you can make an equationbefore you can make an equation
Try AgainTry Again
CorrectCorrect
SETTING UP THE EQUATIONSSETTING UP THE EQUATIONSwhich is correct?which is correct?
OHgCHOHmolCH
OHgCHx
molCO
OHmolCHx
gCO
molCOgCOx 3
3
3314.9
1
93.58
1
1
05.32
168.1
OHgCHOHmolCH
OHgCHx
molCO
OHmolCHx
gCO
molCOgCOx 3
3
3314.9
1
05.32
1
1
93.58
168.1
SETTING UP THE SETTING UP THE EQUATIONSEQUATIONS
OHCHOHmolCH
OHCHx
molH
OHmolCHx
gH
molHxgH 3
3
3
2
3
2
22 12.14
1
202
2
1
05.32
178.1
OHCHOHmolCH
OHCHx
molH
OHmolCHx
gH
molHxgH 3
3
3
2
3
2
22 12.14
1
05.32
2
1
202
178.1
Which element is limiting?Which element is limiting?16.8gCo = 9.14gCH16.8gCo = 9.14gCH33OHOH1.78gH1.78gH2 2 = 14.12gCH= 14.12gCH33OHOH
CoCo HH22
INCORRECT, remember that INCORRECT, remember that the smaller number symbolizes the smaller number symbolizes a limiting reactant. And larger a limiting reactant. And larger number will have an excessive number will have an excessive amountamount
Which element is excessive?Which element is excessive? 16.8gCo = 9.14gCH 16.8gCo = 9.14gCH33OHOH1.78gH1.78gH2 2 = 14.12gCH= 14.12gCH33OHOH
CoCo HH22
CONGRATULATIONSCONGRATULATIONS
• You now know how to do You now know how to do stoichiometry stoichiometry
INCORRECTINCORRECT
•
INCORRECTINCORRECT
•
