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# Atom economy watch

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1. Hey guys, in atom economy we do use the excess moles of the theoretical yield? plus how do we identify which one of the two reactants are in excess. Is it the one with a greater number of moles?

Example Question: When 5.00g of ethanol reacts with 8.00g of ethanoic acid, 7.12g of ethyl ethanoate is produced. Whats the percentage yield?

How would y'all go about working this one out (what i really want to know is how to identify the excess reactant)

If you haven't already gussed, this is chemistry
2. Sorry you've not had any responses about this. Are you sure you’ve posted in the right place? Posting in the specific Study Help forum should help get responses.

I'm going to quote in Tank Girl now so she can move your thread to the right place if it's needed.

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(Original post by Tank Girl)
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3. [QUOTE=TSR Jessica;60565325]Sorry you've not had any responses about this. Are you sure you’ve posted in the right place? Posting in the specific Study Help forum should help get responses.

I'm going to quote in Tank Girl now so she can move your thread to the right place if it's needed.

Don't think I've posted for anything on Atom Economy - CD
Hey guys, in atom economy we do use the excess moles of the theoretical yield? plus how do we identify which one of the two reactants are in excess. Is it the one with a greater number of moles?

Example Question: When 5.00g of ethanol reacts with 8.00g of ethanoic acid, 7.12g of ethyl ethanoate is produced. Whats the percentage yield?

How would y'all go about working this one out (what i really want to know is how to identify the excess reactant)

If you haven't already gussed, this is chemistry
a. You need to find the moles first e.g. 5.00g of ethanol is how many moles? [mass/Mr] and so on.
b. from the equation i.e.

CH3CH2OH + CH3COOH --> CH3COOCH3 + H2O
mole ratio 1 1 1 1
Gram 5.00 8.00 7.12
mole ? ? ?

c. Check if you had used 5g ethanol then how many gram of ethanoic acid you'll need. If 8 gram is more than the theoretical amount, then you've excess ethanoic acid. Similarly you can check if you've excess ethanol if you had used 8 gram of ethanoic acid. IMHO, the question you've asked is slightly incomplete.

BTW,

%Atom economy = (mass of desired product / total mass of reactants) x 100
5. (Original post by CurrentDude)
a. You need to find the moles first e.g. 5.00g of ethanol is how many moles? [mass/Mr] and so on.
b. from the equation i.e.

CH3CH2OH + CH3COOH --> CH3COOCH3 + H2O
mole ratio 1 1 1 1
Gram 5.00 8.00 7.12
mole ? ? ?

c. Check if you had used 5g ethanol then how many gram of ethanoic acid you'll need. If 8 gram is more than the theoretical amount, then you've excess ethanoic acid. Similarly you can check if you've excess ethanol if you had used 8 gram of ethanoic acid. IMHO, the question you've asked is slightly incomplete.

BTW,

%Atom economy = (mass of desired product / total mass of reactants) x 100
Ahhhhhh that makes more sense now, thank you v much

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Updated: November 13, 2015
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