ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: matt123 on November 10, 2010, 05:27:16 pm

Title: WHATS THE POINT OF A POROUS BARRIER?
Post by: matt123 on November 10, 2010, 05:27:16 pm
I read somewhere that they ONLY use these barriers in fuel cells and not normal redox galvanic cells.

Why is this?
I thought they were used to allow conductivity and to separate the reactants?
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: matt123 on November 10, 2010, 05:31:57 pm
?
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: stonecold on November 10, 2010, 05:36:28 pm
Lets the gases out and allows for the electrolyte to pass through without reactants coming into contact and spontaneously reacting.
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: menashiiii on November 10, 2010, 05:37:07 pm
i did this question in the neap book yesterday
it says the use of the porous barrier is to disable contact between the two reactants
so that therefore they are unable to react

hope that helps dude :)
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: Martoman on November 10, 2010, 05:38:32 pm
yeha but they can't ask us a question on the electrolysis of alumina or the Hall or Downs cell unless they give us a diagram with the appropriate info??
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: menashiiii on November 10, 2010, 05:40:26 pm
yeha but they can't ask us a question on the electrolysis of alumina or the Hall or Downs cell unless they give us a diagram with the appropriate info??
we seriously dont know what vcaa is capable of
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: Martoman on November 10, 2010, 05:43:12 pm
I don't think so. They would want application of knowledge not the whole state's vomit on the exam papers.  :buck2:
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: menashiiii on November 10, 2010, 05:46:17 pm
I don't think so. They would want application of knowledge not the whole state's vomit on the exam papers.  :buck2:
bah
they're pretty sick, never know
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: matt123 on November 10, 2010, 05:57:18 pm
Lets the gases out and allows for the electrolyte to pass through without reactants coming into contact and spontaneously reacting.

Then can we use them in Galvanic cells ( or no , because they are 2 separate cells ?)
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: Studyinghard on November 10, 2010, 06:06:53 pm
Lets the gases out and allows for the electrolyte to pass through without reactants coming into contact and spontaneously reacting.

Then can we use them in Galvanic cells ( or no , because they are 2 separate cells ?)

separate cells so no.
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: fady_22 on November 10, 2010, 06:09:59 pm
A fuel cell is a galvanic cell.
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: will74 on November 10, 2010, 06:12:09 pm
In general I think a porous barrier is used to let some ions pass through to each electrode but not others. For whatever reason I guess depends on the context of the question?
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: Potter on November 10, 2010, 06:17:47 pm
As far as i know, the porous barrier serves the same purpose as a salt bridge.
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: masonnnn on November 10, 2010, 07:13:45 pm
yeah from all that i'm getting the idea that a porous barrier is identical to a salt bridge but, the set up looks different...
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: VCE123456789 on November 10, 2010, 07:23:50 pm
yeah from all that i'm getting the idea that a porous barrier is identical to a salt bridge but, the set up looks different...
Yer thats exactly right.
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: Studyinghard on November 10, 2010, 07:25:23 pm
yeah from all that i'm getting the idea that a porous barrier is identical to a salt bridge but, the set up looks different...
Yer thats exactly right.

but a porous barrier is used in a cell ( cant remember ) where the Na+ ions go through the barrier and connect to the OH- ions that make NaOH which is used for stuff. So i guess its not the EXACT same purpose
which cell is this, anyone remember?
Title: Re: WHATS THE POINT OF A POROUS BARRIER?
Post by: jasonn93 on November 10, 2010, 08:53:29 pm
nelson / diaphragm cell i think :)