electro series and the double arrow?

[Martoman]

For exam purposes when it asks to write down the half equation for reaction in electrolysis or anything involving the series do we have to include the double arrow to giain full marks? In SACS the  teacher was like meh ceebs.

[superflya]

i thought it was a single arrow, no??

[Martoman]

but there are double arrows in the elctro series >.<

[Xavier1234]

For exam purposes when it asks to write down the half equation for reaction in electrolysis or anything involving the series do we have to include the double arrow to giain full marks? In SACS the  teacher was like meh ceebs.

irena chemistry says include the double arrow so as to be safe. however, be logical since some questions specifically state full completion so yeah thats gotta be single on those.

[scocliffe09]

Mao commented on this or something similar in another thread, I think.
Usually when you're doing electrolysis, if you have sufficient voltage, you don't notice the back reaction/ the back reaction occurs minimally, so we often write a single arrow - it makes sense.
Essentially I am pretty sure though (and this is what my chem teacher has said) if you write a double arrow they cannot mark you wrong, because even "complete reactions" like, for example, ionisation of HCl, are still equilibrium systems with a forward and back reaction which both occur, even if the back reaction is occurring minimally. So if you're worried stick to a double arrow.

[_henwee]

For exam purposes when it asks to write down the half equation for reaction in electrolysis or anything involving the series do we have to include the double arrow to giain full marks? In SACS the  teacher was like meh ceebs.

irena chemistry says include the double arrow so as to be safe. however, be logical since some questions specifically state full completion so yeah thats gotta be single on those.

Irena told us different at end-of-year revision lecture. =/
She told us that it's shown as double arrows because it demonstrates that it can go both ways dependent on whether its an oxidant or reductant, however, when you write it, you define exactly which way it is going - something along those lines.


Do you use the equilibrium arrows in the overall equations for galvanic and electrolytic cells?
 
No – single arrows must be used. When we are dealing with a cell, we assume that either a
spontaneous or non spontaneous reaction occurs, and must therefore use a single arrow.

[Xavier1234]

For exam purposes when it asks to write down the half equation for reaction in electrolysis or anything involving the series do we have to include the double arrow to giain full marks? In SACS the  teacher was like meh ceebs.

irena chemistry says include the double arrow so as to be safe. however, be logical since some questions specifically state full completion so yeah thats gotta be single on those.

Irena told us different at end-of-year revision lecture. =/
She told us that it's shown as double arrows because it demonstrates that it can go both ways dependent on whether its an oxidant or reductant, however, when you write it, you define exactly which way it is going - something along those lines.


Do you use the equilibrium arrows in the overall equations for galvanic and electrolytic cells?
 
No – single arrows must be used. When we are dealing with a cell, we assume that either a
spontaneous or non spontaneous reaction occurs, and must therefore use a single arrow.

yet again my memory has failed me. thanks for the clear up!

[scocliffe09]

Although it might be more correct to use a single arrow, I would still argue you cannot be marked wrong for using an equilibrium arrow, unless a particular question states "to completion" or something of the like.

[cameron_15]

If it asks for a reduction or oxidation reaction, surely it cannot go both ways as then one reaction would be oxidation and one would be reduction?

I haven't ever written half equations with the double arrows...

[Martoman]

No it can thats the point. Its just the overall effect is the electrons flowing to one side.

[chem-nerd]

Galvanic/electrolysis - Make sure you use single arrows - otherwise it looks like you're hedging your bets and can't determine whether oxidation or reduction is occurring.

[cameron_15]

No it can thats the point. Its just the overall effect is the electrons flowing to one side.

I'm sure that both reactions occur, if it asks for an oxidation reaction and you show that correctly but with two arrows, the reverse reaction would be a reduction reaction and therefore not included... That's just my logic anyway...

[masonnnn]

each post goes back and forth from 'use one arrow' to 'use both arrows'
...
i'd say do both arrows unless it's specified that it's goes to completion...can't really go wrong can you?

[stonecold]

just use the single arrow people

/thread...

[kyzoo]

my teacher told me to use single arrow 0.o