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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 330315 times)

Offline the_grim_reaper

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2025 on: May 24, 2010, 07:21:31 pm »
Quote from: A@di on May 24, 2010, 07:08:14 pm
i cant open that paper??!!


Sorry for the delay.....
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2026 on: May 24, 2010, 07:23:29 pm »
Quote from: deadman786 on May 24, 2010, 07:21:31 pm

Sorry for the delay.....

is the ans C ??
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Offline Baladya

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2027 on: May 24, 2010, 07:23:57 pm »
Quote from: Horse Lover on May 24, 2010, 07:17:41 pm
CAN SOMEONE PLEASE TELL ME WHAT IS PRECIPITATION???

Also... when the give u an equation.. how do u know if it is a redox or oxidation???

Please Notify me :)

Precepitation is when a solid forms when two liquids are mixed together (for example neutralisation reactrions)
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Offline Horse Lover

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2028 on: May 24, 2010, 07:25:03 pm »
Thanks ...

now can someone tell me.. how do u know if an equation is given if the reaction is redox or oxidizing??
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2029 on: May 24, 2010, 07:25:41 pm »
Quote from: deadman786 on May 24, 2010, 07:21:31 pm

Sorry for the delay.....

Clearly the ms is rong if it says ph>7.
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2030 on: May 24, 2010, 07:26:10 pm »
Quote from: Horse Lover on May 24, 2010, 07:25:03 pm
Thanks ...

now can someone tell me.. how do u know if an equation is given if the reaction is redox or oxidizing??
check the previous pages for a sample solved question on exactly the same thing
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Offline rhea

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2031 on: May 24, 2010, 07:28:10 pm »
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Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2032 on: May 24, 2010, 07:30:27 pm »
Quote from: rhea on May 24, 2010, 07:28:10 pm
shouldnt it be A?


above 7 would be basic .. the other option says blue to red .. shows for acidic
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2033 on: May 24, 2010, 07:34:20 pm »
ALRIGHTY THEN !

GOOD LUCK GUYS 2MRW

ILL LEAVE YOU TONGIHT WITH MR. AADII AND MR. VIN TO ASNWER YOUR QUESTIONS !!! I WISH ALL OF YOU THE BEST OF LUCK !! AND IF U WANNA LIGHTEN UP GO VISIT THE JOKES AND RIDDLES POSTS ( LORD KRATOS <3)


GOOD LUCK AGAIN

AND THANKS VIN AND AADI


GOOOOOOOOOD NIIIIIIIGHHHHHHHHHTTTTTTTTTTTTTTT SF!
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Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2034 on: May 24, 2010, 07:35:38 pm »
Quote from: Kimo Jesus on May 24, 2010, 07:34:20 pm
ALRIGHTY THEN !

GOOD LUCK GUYS 2MRW

ILL LEAVE YOU TONGIHT WITH MR. AADII AND MR. VIN TO ASNWER YOUR QUESTIONS !!! I WISH ALL OF YOU THE BEST OF LUCK !! AND IF U WANNA LIGHTEN UP GO VISIT THE JOKES AND RIDDLES POSTS ( LORD KRATOS <3)


GOOD LUCK AGAIN

AND THANKS VIN AND AADI


GOOOOOOOOOD NIIIIIIIGHHHHHHHHHTTTTTTTTTTTTTTT SF!

gd night kimo  :D  ..Talk to you later  ;)
« Last Edit: May 24, 2010, 07:38:59 pm by the golden girl »
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2035 on: May 24, 2010, 07:39:22 pm »
Someone please explain.  I don't get!  Especially why last one isnt redox.  Thanks
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2036 on: May 24, 2010, 07:42:14 pm »
S + 02 --> S02

S - oxidation number 0..
O2 - oxidation number 0

SO2 --> oxidation number of O = (-2*2) = -4 , thus oxidation number of S = +4

S--> 0 to 4 oxidation
O -> 0 to -4 reduction

thus redox.

2S02 + 02-->2 S03

2SO2 -> oxidation number of O = (-2*2) = -4, thus S = +4.  O2 -> 0, final of O = -4+0 = -4

SO3--> Oxidation number of O = (-2*3) = -6, of S = +6

Final , S --> 4 to 6 oxidation

         O --> -4 to -6 reduction

SO3 + H20--> H2SO4

SO3 --> O = (-3*2) = -6 , thus S = +6

H2O --> O = -2, thus H = +2

O in both compounds thus, final number of O = -6-2 = -8

H2SO4--> O = (-2*4) = -8, thus H = +2, as final oxidation number of the compound shud be 0, -8+2+S = 0

thus, S = +6

now the changes

S --> 6 to 6
H --> 2 to 2
O --> -8 to -8..

NOt redox.
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Offline Shazizzzle

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2037 on: May 24, 2010, 07:43:47 pm »
Quote from: A@di on May 24, 2010, 05:33:17 pm
this drove me crazy during my IGCSEs too..

S + 02 --> S02

S - oxidation number 0..
O2 - oxidation number 0

SO2 --> oxidation number of O = (-2*2) = -4 , thus oxidation number of S = +4

S--> 0 to 4 oxidation
O -> 0 to -4 reduction

thus redox.

2S02 + 02-->2 S03

2SO2 -> oxidation number of O = (-2*2) = -4, thus S = +4.  O2 -> 0, final of O = -4+0 = -4

SO3--> Oxidation number of O = (-2*3) = -6, of S = +6

Final , S --> 4 to 6 oxidation

         O --> -4 to -6 reduction

SO3 + H20--> H2SO4

SO3 --> O = (-3*2) = -6 , thus S = +6

H2O --> O = -2, thus H = +2

O in both compounds thus, final number of O = -6-2 = -8

H2SO4--> O = (-2*4) = -8, thus H = +2, as final oxidation number of the compound shud be 0, -8+2+S = 0

thus, S = +6

now the changes

S --> 6 to 6
H --> 2 to 2
O --> -8 to -8..

NOt redox.



In the first one, why are the oxidation state of S and of 02 zero? :S
Thanks. :)
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Offline ambitious94

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2038 on: May 24, 2010, 07:44:56 pm »
The equation shows the reaction between a halogen and the aqueous ions of another halogen.
X2 + 2Y- ? 2X- + Y2
What could X2 and the colour of Y– be?

A chlorine, brown
B chlorine, colourless
C iodine, brown
D iodine, colourless

Answer is B..... ??? ??? ??? :-\ HOWWWWWWWWWWWWWW? Plzz help me out someone!
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Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #2039 on: May 24, 2010, 07:46:23 pm »
Quote from: Shazizzzle on May 24, 2010, 07:43:47 pm
In the first one, why are the oxidation state of S and of 02 zero? :S
Thanks. :)

Oxidation States of Elements is always 0. Its a rule.

"The oxidation number of any free element is zero."

here : http://www.chemistry.wustl.edu/~courses/genchem/Labs/RedoxIdentity/oxidation.htm

3rd one
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