The Periodic Table

Absolute electrode potential, in electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). == Definition == According to a more specific definition presented by Trasatti, the absolute electrode potential is the difference in electronic energy between a point inside the metal (Fermi level) of an electrode and a point outside the electrolyte in which the electrode is submerged (an electron at rest in vacuum). This potential is difficult to determine accurately....

DHMO

@Biker how did you calculate that?

Biker

Calculate what? it is on wikipedia

DHMO

@Biker I mean the 4.52 eV above

Biker

Well take the energy and divide it by the charge of electron

you get the voltage

DHMO

How did you calculate the energy?

wait

the 4.52 eV was the energy of 2H -> H2, right

Biker

5:31 AM

Yes

well, voltage

DHMO

but I thought you were trying to find the voltage of 2H+ + 2e- -> H2

@Biker eV is energy

Biker

Well isnt it the same? if you reverse

DHMO

How are they the same?

Biker

It should conserve energy

DHMO

but 2H -> 2H+ + 2e- takes energy

Biker

5:36 AM

Yes and the other reaction releases

DHMO

but the energy of 2H -> H2 should not equal the energy of 2H+ + 2e- -> H2

Biker

:/

DHMO

@Biker Wait, I might have a clue

@Biker because H+(g) is not H+(aq)

Biker

Ah

DHMO

H2 -> 2H+(aq) (0eV)

this reaction is 0

Biker

5:39 AM

Well it is zero because we have set it to zero, isnt that right?

DHMO

No, this is really zero

Standard enthalpy of formation

The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the compound from its constituent elements, with all substances in their standard states at 1 atmosphere (1 atm or 101.3 kPa). Its symbol is ΔHo f or ΔfHo. The superscript theta (zero) on this symbol indicates that the process has occurred under standard conditions at the specified temperature (usually 25 °C or 298.15 K). Standard states are as follows: For a gas: the standard state is a pressure of exactly 1 atm For a solute present in an ideal solution: a...

wait

then where are the electrons?

@Biker Should I take it to main?

Biker

Eehhh, I will study that chapter later then come back. might have a clue then

Main?

@Biker the main site

Yea please

Alright

5:52 AM

@DHMO ?

DHMO

@Biker typing up a question isn't that easy, be patient

Biker

:C

DHMO

0

Q: Discrepancy in Standard Hydrogen Electrode energy

From Absolute Electrode Potential on Wikipedia: $$\ce{\frac12H2(gas) -> H+(aq) + e-(g)\quad(-(4.44\pm0.02)eV)}$$ The bond-dissociation energy of hydrogen is $\ce{4.52 eV}$: $$\ce{\frac12H2 -> H\quad(-2.26 eV)}$$ The ionization energy of hydrogen is $\ce{13.6 eV}$: $$\ce{H -> H+ + e- (-13.6 e...

energy

@Biker

Biker

Thank you :D

I just would love to have a professional chemist and ask him all the questions that I have XD

DHMO

6:52 AM

@Biker i am far from a professional chemist, you may consult @orthocresol or @Loong or @Wildcat (sorry for the pings)

Biker

7:08 AM

Why do Ag atoms form negative photograph

DHMO

7:30 AM

@Biker what do you mean?

Biker

I mean in photography you have AgBr when Br gets hit by a photon/light it oxidizes and Ag gets reduced so you form Ag atoms

The resulting picture is negative which means The lighter the object is the darker it is in the picture

Aaron Abraham

Terminology issue here........is it correct if I term a reaction intermediate's [Grignard reagent-Carbonyl group adduct] breakdown as 'decomposition' ? (I don't really see anything wrong with that, but just in case.......@DHMO , since you're picky with terms......any ideas, please? )

DHMO

@AaronAbraham no idea

Aaron Abraham

Darn.......

Trying to figure out how I need to frame my next question.....

But thanks anyway......

DHMO

@Biker no idea as well