IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: buzywidbizworld on November 06, 2009, 02:33:07 pm

Title: Help wid chemistry
Post by: buzywidbizworld on November 06, 2009, 02:33:07 pm: can any1 tell me wat am i suppose 2 knw in fuel cells because am thoroughly confused ??? wid the topic.

wat shud i write if am aked to define exothermic? am i suppoed to write bout da bond formin or bout da release of heat.
Title: Re: Help wid chemistry
Post by: Ghost Of Highbury on November 06, 2009, 03:22:20 pm: Exothermic is heat given out, and this happens when new bonds are formed. The energy change is negative.
Title: Re: Help wid chemistry
Post by: Ghost Of Highbury on November 06, 2009, 03:24:43 pm: fuel cells with acid electrolyte..

heres. it..

the hydrogen (H2) loses electrons.. 2H2 --> 4H+ + 4e- which travel through the circuit to the cathode and react with O2..also the H+ ions from the acid electrolyte meets the electrons and O2 at the cathode

the reaction

O2 + 4H+ + 4e- = 2H2O
----------------------------------
with NaOH

Then the reactions are as follows:-
At anode: 2H2 + 4OH(-) --->4H2O + 4e(-)
At cathode: O2 + 4e(-) +2H2O ---->4OH(-)

anode - the hydrogen supplied reacts with the OH- ion form NaOH and forms water and electrons. Electrons flow round the circuit (electricity) and react at the cathode with water and O2 supplied.

The OH- ions removed at the anode are replaced by those formed at the cathode.
Title: Re: Help wid chemistry
Post by: @d!_†oX!© on November 07, 2009, 09:03:50 am: https://studentforums.biz/index.php/topic,4304.0.html

this is the place fr u to go buzywidbizworld
Title: Re: Help wid chemistry
Post by: buzywidbizworld on November 07, 2009, 03:40:47 pm: Hey Aadi n aditoxic,
Thanks alot nw am very much clear wid da topic.
Title: Re: Help wid chemistry
Post by: dlehddud on November 09, 2009, 05:57:49 am: Quote from: @d!_†oX!© on November 07, 2009, 04:08:08 pm
anytime dude!!! :)

buzywidbizworld's a girl isn't she? lol
Title: Re: Help wid chemistry
Post by: ~~~~shreyapril~~~~ on November 09, 2009, 06:51:18 am: so wat why cant a girl be dude???
Title: Re: Help wid chemistry
Post by: dlehddud on November 09, 2009, 07:31:40 am: Quote from: ~~~~shreycool~~~~ on November 09, 2009, 06:51:18 am
so wat why cant a girl be dude???

i thought dude is used when referring to a guy? isn't it?
Title: Re: Help wid chemistry
Post by: ~~~~shreyapril~~~~ on November 09, 2009, 07:33:23 am: pata nahin!!