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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 357284 times)

Offline nits94

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #180 on: November 11, 2009, 03:26:20 pm »
but isnt it always H2 and not H+???
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Offline $!$RatJumper$!$

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #181 on: November 11, 2009, 03:28:27 pm »
no not always... Hydrogen can also b expressed as an ion.. it just depends on the question...
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Offline nits94

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #182 on: November 11, 2009, 03:29:18 pm »
o got it :) :)
« Last Edit: November 11, 2009, 03:31:21 pm by nits94 »
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Offline adorabledaughter_07

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #183 on: November 11, 2009, 03:30:37 pm »
i thought aditox ws rite..bt how cn hydrogen combine wid o2?..Ca is mor reactive rite??
nits..its hydrogen ions..so h+..
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #184 on: November 11, 2009, 03:31:11 pm »
arrey nits u gotta understand this...
its not a normal reaction between hydrogen and calcium oxide...
its the reaction for the treatment of acidity of the soil
so here H+ represents the ion from the acid...
u get it now??
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Offline nits94

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #185 on: November 11, 2009, 03:31:47 pm »
ya fine Thanks :) :) got confused
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Offline eightAs

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #186 on: November 11, 2009, 03:32:44 pm »
Quote from: nits94 on November 11, 2009, 03:29:18 pm
hw??? I dint get it
CaO + H+(1) ---> Ca2+ + H2O(2)
H at (1) exists as an ion cos its from an acid. An acid ionizes completely or partially, meaning they split up into ions. eg.: HCl splitting into H+ and Cl-. At (2) its not H+ and OH- cos water is formed which does not ionize. I hope you get it.
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Offline adorabledaughter_07

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #187 on: November 11, 2009, 03:39:49 pm »
question- how doz hydrogn combine wid O2? ca is mor reactive>
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #188 on: November 11, 2009, 03:41:55 pm »
here we are not talking about a displacement reaction...its a neutralization reaction where water has to form by combing H and OH/O
do u get it now??
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Offline ruchir.sakhrani

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #189 on: November 11, 2009, 03:43:39 pm »
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #190 on: November 11, 2009, 03:45:01 pm »
that's paper 1...
what do u mean by 4 b 2 and 4 b 3??????????
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Offline ~~~~shreyapril~~~~

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #191 on: November 11, 2009, 03:45:22 pm »
this is MCQ question!!
how can you expect 4b2 and 4b3???
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Offline adorabledaughter_07

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #192 on: November 11, 2009, 03:47:47 pm »
@aditoxic- oh got it..din notiz dat..thankz! :)
« Last Edit: November 11, 2009, 03:49:47 pm by adorabledaughter_07 »
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Offline ruchir.sakhrani

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #193 on: November 11, 2009, 03:54:35 pm »
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Offline Ghost Of Highbury

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #194 on: November 11, 2009, 04:11:27 pm »
4bii) first understand the q.

       FeCl3 + 3NaOH --> Fe(OH)3 + 3NaCl

moles of FeCl3 = conc. * volume = 1 * 4/1000 = 0.004

MOles of NaOH = 0.004*3 = 0.012 or conc. * volume = 1 * 12/1000 (look at graph)  = 0.012

when FeCl2 is used, this is the equation

FeCl2 + 2NaOH --> Fe(OH)2 + 2NaCl

Moles of FeCl2 = conc. * volume = 0.004

but here, the mole ratio is 1:2

so the moles of NaOH = 0.004 * 2 = 0.008

volume = moles/conc. = 0.008/1 = 0.008dm^3 = 8cm^3

thus, for FeCl2 --> 8cm^3 of NaOH reacts completely with FeCl2, so, the shape wud be same, only it wud become constant (parallel to x-axis) at 8cm^3 of NaOH
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