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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 353782 times)

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2055 on: May 24, 2010, 08:04:22 pm »
Quote from: Ivo on May 24, 2010, 08:02:43 pm
Has been answered previously

where , give me the link ,or number of page plz ???
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2056 on: May 24, 2010, 08:04:54 pm »
Both the options can be used, however, having molten CuSO4 uses more energy and thus its wiser to use aqueous copper sulfate.
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Offline Helium

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2057 on: May 24, 2010, 08:06:12 pm »
Q)

What is a Basic oxide?
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2058 on: May 24, 2010, 08:07:20 pm »
Quote from: the golden girl on May 24, 2010, 07:47:54 pm
plz explain Q20 year november 2007  

thx in advance

answer is B .. because carbon will react with oxygen from air to form CO2 and escape .. so mass of carbon dec.

copper reacts with O2 to form oxide which 'gains' mass due to oxygen
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2059 on: May 24, 2010, 08:07:28 pm »
Quote from: the golden girl on May 24, 2010, 08:04:22 pm
where , give me the link ,or number of page plz ???

carbon reacts with air to form carbon dioxide, released, so mass of carbon decreases.

copper reacts wtih oxygen to form copper oxide, which is soluble, so gets accumulated.

so answer is b
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2060 on: May 24, 2010, 08:07:38 pm »
Quote from: Ivo on May 24, 2010, 08:00:54 pm
So all compunds have oxidation number of 0?

Then why is it that sulphur is +4, i thought cos it's in group 6, then it is -2.

how do oxidation numbers work?

its not possible to explain everything now...its a long long concept..

check the website i had posted earlier and read the rules..that shud help u

@helium = a metal oxide that is base, which forms a hydroxide when ombined with water.
i didnt say all compounds have oxidation number of 0, the OVERALL! oxidation number is 0...like SO2, if O2's is -4, then S's shud be +4 to make the overall oxidation number 0.
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Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2061 on: May 24, 2010, 08:07:56 pm »
Quote from: Helium on May 24, 2010, 08:06:12 pm
Q)

What is a Basic oxide?

metal oxide


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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2062 on: May 24, 2010, 08:08:44 pm »
Quote from: A@di on May 24, 2010, 08:07:38 pm
its not possible to explain everything now...its a long long concept..

check the website i had posted earlier and read the rules..that shud help u

@helium = a metal oxide that is base, which forms a hydroxide when ombined with water.
i didnt say all compounds have oxidation number of 0, the OVERALL! oxidation number is 0...like SO2, if O2's is -4, then S's shud be +4 to make the overall oxidation number 0.


sory which website?
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Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2063 on: May 24, 2010, 08:08:58 pm »
Quote from: Ivo on May 24, 2010, 08:07:28 pm
carbon reacts with air to form carbon dioxide, released, so mass of carbon decreases.

copper reacts wtih oxygen to form copper oxide, which is soluble, so gets accumulated.

so answer is b

what abt Q35  :-[ :-[
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2064 on: May 24, 2010, 08:09:14 pm »
Quote from: Helium on May 24, 2010, 08:06:12 pm
Q)

What is a Basic oxide?

*ahem* google ..  :P

reacts with acid to give salt and water
reacts with water to give a base
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2065 on: May 24, 2010, 08:10:11 pm »
Quote from: Ivo on May 24, 2010, 08:07:28 pm
carbon reacts with air to form carbon dioxide, released, so mass of carbon decreases.

copper reacts wtih oxygen to form copper oxide, which is soluble, so gets accumulated.

so answer is b

35) A , K + Na = 1 + 6.5 = 7.5
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2066 on: May 24, 2010, 08:10:57 pm »
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Offline Helium

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2067 on: May 24, 2010, 08:11:53 pm »
Quote from: ~VIN1094~ on May 24, 2010, 08:09:14 pm
*ahem* google ..  :P

reacts with acid to give salt and water
reacts with water to give a base
Thanks thats what i wanted
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2068 on: May 24, 2010, 08:12:26 pm »
Quote from: the golden girl on May 24, 2010, 07:53:18 pm
??? ??? ??? :-\ :-\ :-\ :-[

i'm waitin   ::) ::)

38) B - it burns in air, it dissolves.. it cannot be polymerized.
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2069 on: May 24, 2010, 08:12:41 pm »
Quote from: the golden girl on May 24, 2010, 08:08:58 pm
what abt Q35  :-[ :-[

ok the only elements "singly" charged are Na and K add 6.5 and 1 = 7.5 ie A
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