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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 350846 times)

Offline buzywidbizworld

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #165 on: November 11, 2009, 02:42:15 pm »
hi
cud u also help me to ans this?
q- why should you be able to predict that metals such as iron and chromium have more thn one oxidation state?
wa8in 4 da reply.
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Offline Saladin

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #166 on: November 11, 2009, 02:42:54 pm »
i get confused. But, shrey is wrong. its to do wid electrons not reactivity.
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Offline ~~~~shreyapril~~~~

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #167 on: November 11, 2009, 02:43:37 pm »
why cant we do it as i said????
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Offline Saladin

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #168 on: November 11, 2009, 02:43:52 pm »
2 buzy

its becasue they are transition metals.
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Offline Saladin

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #169 on: November 11, 2009, 02:45:20 pm »
Its a redox question u see. and redox questions ask about valence electrons. So reacticity is about displacement reactions. But this is redox. and anyways, u r wrong, as transition metals behave differently under different circumstances.
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #170 on: November 11, 2009, 02:46:07 pm »
Quote from: buzywidbizworld on November 11, 2009, 02:42:15 pm
hi
cud u also help me to ans this?
q- why should you be able to predict that metals such as iron and chromium have more thn one oxidation state?
wa8in 4 da reply.
1)because they are transition metals
2)due to their presence in different forms...ex, FeSO4 and FeCl3
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Offline Saladin

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #171 on: November 11, 2009, 02:47:51 pm »
for adi toxic's second point, its restating what they said in the q. unless u are given examples of same metals reacting differently, u shud not give the second point.
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #172 on: November 11, 2009, 02:49:49 pm »
i think u should cuz just stating that they are transition metals doesn't score u full marks...if i remember correctly i have  seen this point in some mark scheme
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Offline buzywidbizworld

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #173 on: November 11, 2009, 02:50:30 pm »
Thanks guys
but Dude aditoxic was ri8 wid da eg.
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Offline Saladin

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #174 on: November 11, 2009, 03:00:14 pm »
i do a level u see, i am starting to think more like an Edexcel markscheme. srry adi toxic, if u felt insulted!! :-[
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #175 on: November 11, 2009, 03:06:21 pm »
llol...not at all dude...i was just trying to tell u that the point was valid that's it...no personal issues man
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Offline adorabledaughter_07

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #176 on: November 11, 2009, 03:19:54 pm »
uhm..can anybody tel me de ionic equation for de reaction between calcium oxide nd hydrogn ionz? ???
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Offline @d!_†oX!©

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #177 on: November 11, 2009, 03:22:01 pm »
CaO + H+ ---> Ca2+ + H2O

« Last Edit: November 11, 2009, 03:26:58 pm by @d!_†oX!© »
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Offline nits94

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #178 on: November 11, 2009, 03:23:31 pm »
wont it be this?? CaO + H2= Ca2+ + OH- + H+ ... it mayb this not sure
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Offline $!$RatJumper$!$

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Re: ~~~All Chemistry Doubts Here~~~
« Reply #179 on: November 11, 2009, 03:25:23 pm »
Quote from: @d!_†oX!© on November 11, 2009, 03:22:01 pm
CaO + H+ ---> Ca2+ + H2O

i think dts right!!

this is right... im sure about it :)
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