chem HL - faraday's constant?

Hello

does anyone know whether for chem HL we need to know the exact formulas to find the mass of product formed in electrolysis.

i.e.
charge = amps x time

moles of electrons = charge passed / 96500

help is appreciated.

Reply 1

ancksha

ofcourse. its not hard, is it :smile:

Once u wrote it u already know it :smile:

)

Reply 2

The Imperator

OP

2

aye, but: no1 in my school has done it, especially since it's not mentioned in Neuss, OR the syllabus (faradays that is)

besides, shouldnt IB provide ALL formulas needed in their blasted data book?

Reply 3

Rashed

when /96500
this is when u change couloumbs to faradays which is moles of e

Reply 4

kraslan

1

The Imperator

Hello

does anyone know whether for chem HL we need to know the exact formulas to find the mass of product formed in electrolysis.

i.e.
charge = amps x time

moles of electrons = charge passed / 96500

help is appreciated.

In the syllabus it states: "Determine the relative amounts of the products formed during the electrolysis of aqueous solutions."

And by the way, it is mentioned in the Neuss study guide, only its not called "Faradays Constant"

My teacher hasnt taught it to us but Im guessing that to predict the relative amounts of product formed, you wont need to do the calculations, but you'll need to understand the concept behind it.

Reply 5

akk713

2

God damn it I lost in electro-chemistry

In electrolysis the anode seems to be the positive electrode,

but in electropotential metal half cells it seems to be negative??!! (where electrons come from it)

Reply 6

ancksha

faraday.. thats weird. our teacher did that too. But its not much to remember. I AGREE, iB SHOULD PUT ALL THE FORMULAS IN THE BOOKLET. Those who took physics might agree that physics data booklet is made much better than chemistry.

Reply 7

kraslan

1

akk713

God damn it I lost in electro-chemistry

In electrolysis the anode seems to be the positive electrode,

but in electropotential metal half cells it seems to be negative??!! (where electrons come from it)

Yes, in electrolysis and Galvanic Cells the (-) and (+) electrodes are switched.

In electrolysis, oxidation occurs at the (+) electrode. (Electrons move to the (-) electrode)

In Galvanic Cells, oxidation occurs at the (-) electrode. (Electrons move to the (+) electrode.

Reply 8

akk713

2

kraslan

Yes, in electrolysis and Galvanic Cells the (-) and (+) electrodes are switched.

In electrolysis, oxidation occurs at the (+) electrode. (Electrons move to the (-) electrode)

In Galvanic Cells, oxidation occurs at the (-) electrode. (Electrons move to the (+) electrode.

Thanks!!

So to avoid confusion

Is it right to say that oxidation ALWAYS occurs at anode??

Reply 9

The Imperator

OP

2

akk713

Thanks!!

So to avoid confusion

Is it right to say that oxidation ALWAYS occurs at anode??

yes

Reply 10

Graffis

kraslan

Yes, in electrolysis and Galvanic Cells the (-) and (+) electrodes are switched.

In electrolysis, oxidation occurs at the (+) electrode. (Electrons move to the (-) electrode)

In Galvanic Cells, oxidation occurs at the (-) electrode. (Electrons move to the (+) electrode.

What really matters is where oxidtation and reduction occur. OA- Oxidation is on Annode. RC - Reduction is on Cathode. and to have the mass of the pptt coating the plate you can use:

m=MIt/zF

where:

m- the unknown mass in g
M - molar mass of the element coating the plate
I - current (A)
t - time (s)
z - number of electrons flowing
F - faraday's cons.

chem HL - faraday's constant?

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