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Topic: EGE Question  (Read 17690 times)

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Offline maakii

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Re: EGE Question
« Reply #15 on: February 13, 2007, 02:01:44 PM »
yes. If for the reaction

X + e- >X-

delta H is lets say -250kJ /mol,

EGE =            -250kJ / mol
EA = -EGE =    250kJ /mol

Offline abcc

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Re: EGE Question
« Reply #16 on: February 13, 2007, 02:10:53 PM »
yes. If for the reaction

X + e- >X-

delta H is lets say -250kJ /mol,

EGE =            -250kJ / mol
EA = -EGE =    250kJ /mol
that means they have the same meaning, but not the same???

Offline maakii

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Re: EGE Question
« Reply #17 on: February 13, 2007, 02:19:02 PM »
Actually EA is just the delta H of the reaction:

X- > X + e-

According to the IUPAC gold book. So it would be negative of EGE ( delta H when reaction X + e- -> X- takes place) , which is the reaction taking place in the other direction.

Offline abcc

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Re: EGE Question
« Reply #18 on: February 13, 2007, 02:24:49 PM »
Actually EA is just the delta H of the reaction:

X- > X + e-

According to the IUPAC gold book. So it would be negative of EGE ( delta H when reaction X + e- -> X- takes place) , which is the reaction taking place in the other direction.
??
electron affinity----- X+ e- > X-

Offline english

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Re: EGE Question
« Reply #19 on: February 13, 2007, 04:41:34 PM »
First EA is negative, not positive.  I don't trust Wikipedia.

Offline maakii

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Re: EGE Question
« Reply #20 on: February 13, 2007, 10:40:14 PM »
You should trust the IUPAC gold book then  :P

http://goldbook.iupac.org/E01977.html

Offline english

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Re: EGE Question
« Reply #21 on: February 13, 2007, 11:02:19 PM »
You should trust the IUPAC gold book then  :P

http://goldbook.iupac.org/E01977.html

Yes, it says it is negative as well:

The equivalent more common definition is the energy released (Einitial-Efinal) when an additional electron is attached to a neutral atom or molecule.

 

Offline abcc

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Re: EGE Question
« Reply #22 on: February 13, 2007, 11:25:22 PM »
First EA is negative, not positive.  I don't trust Wikipedia.
if EA is -ive,
EGE also is -ive....
then why EA=-EGE ???

Offline abcc

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Re: EGE Question
« Reply #23 on: February 13, 2007, 11:26:35 PM »
You should trust the IUPAC gold book then  :P

http://goldbook.iupac.org/E01977.html
THX FOR the reference ;D

Offline english

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Re: EGE Question
« Reply #24 on: February 14, 2007, 06:57:26 AM »
First EA is negative, not positive.  I don't trust Wikipedia.
if EA is -ive,
EGE also is -ive....
then why EA=-EGE ???

Quote
The 1st Electron Affinity of an element is the enthalpy change when 1 mole of gaseous atoms of that element each gain an electron to form gaseous ions each with a single negative charge.  Often exothermic as the negative electron is attracted to positive nucleus.

Maybe that will help.

Offline abcc

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Re: EGE Question
« Reply #25 on: February 14, 2007, 07:47:44 AM »
First EA is negative, not positive.  I don't trust Wikipedia.
if EA is -ive,
EGE also is -ive....
then why EA=-EGE ???

Quote
The 1st Electron Affinity of an element is the enthalpy change when 1 mole of gaseous atoms of that element each gain an electron to form gaseous ions each with a single negative charge.  Often exothermic as the negative electron is attracted to positive nucleus.

Maybe that will help.
sooooo
EA is -ive as it is exothemic
then that means EA = EGE  ???
BUT SOMEONE said EA = - EGE

Offline english

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Re: EGE Question
« Reply #26 on: February 14, 2007, 07:58:33 AM »
No!

EGE and EA are the same thing.  You don't say that because EA is negative, and EGE is negative, then EA = EGE.

EA = -EGE

or

EA = -kJ/mol

Offline abcc

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Re: EGE Question
« Reply #27 on: February 14, 2007, 11:12:42 AM »
No!

EGE and EA are the same thing.  You don't say that because EA is negative, and EGE is negative, then EA = EGE.

EA = -EGE

or

EA = -kJ/mol
???
but if they are the same,
why do they have different 'sign'???
-ive and + ive have different meanings respectively.
give an example: if EA= -165, then EGE = +165( since EA= - EGE)
they have same magnitude and meaning ???
but - ive means energy realeased to surrounding; +ive means energy absorbed .

Offline maakii

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Re: EGE Question
« Reply #28 on: February 14, 2007, 01:41:16 PM »
You should trust the IUPAC gold book then  :P

http://goldbook.iupac.org/E01977.html

Yes, it says it is negative as well:

The equivalent more common definition is the energy released (Einitial-Efinal) when an additional electron is attached to a neutral atom or molecule.

 

The Einitial is higher than Efinal if energy is released when an additional e- is attached to a neutral atom/molecule, so it should be positive.

Offline abcc

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Re: EGE Question
« Reply #29 on: February 14, 2007, 03:06:45 PM »
i am still confuseddddd :'(

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