Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 334152 times)

Offline Baladya

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1935 on: May 24, 2010, 05:54:31 pm »
I hope someone can still answer my doubt.

Can anyone list down all the colours of Metals, non-metals, gases and everything else that's included in the syllabus for Paper 1? (Including Hydroxide, etc..) There are a lot of questions about it especially in electrolysis. Plus the oxides of metals

Bromine: brown
Chlorine: green
Iodine: grey
lead: silver
Looks like i ran out of cool signatures :|

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1936 on: May 24, 2010, 05:56:14 pm »
You might have .. u should have done this for paper 6 :-\

VIN thx , i don't kno what the heck is wrong with me today  >:(......

thx for baring with me (that's what our supervisor says whenever sh e reads the rules and regulations of ig exam ...so hilarious  , i keep laughin with my self most of the time she's readi cuz i memorixed it people :P)
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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1937 on: May 24, 2010, 05:56:39 pm »
since when did metals react with bases?

asnwr is B
NO secrets to SUCCESS , it is the result of 1.HARD WORK 2.GOOD PREPARATION 3.LEARNING FROM FAILURE
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1938 on: May 24, 2010, 05:56:45 pm »
LOLS!  Which paper and year was it?

XD hahaha.. it's M/J 06 Physics P1 :P
there are almost.. 5 blank questions :P
You said I must eat so many lemons cause I am so bitter.

Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1939 on: May 24, 2010, 05:57:06 pm »
yo ari u saw my message?

By the way guys: When is hydrogen produced from cracking?

     H    H                           H    H
     |    |        (steam)         |     |
H- C - C - H   ---------->    C = C    +   H2
     |    |        (>800 *C)      |     |
     H    H                           H     H

ETHANE                             ETHENE      HYDROGEN ;)


 

Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1940 on: May 24, 2010, 05:57:22 pm »
since when did metals react with bases?

asnwr is B

lol this has nothing to do with metals reacting with bases? ...
You said I must eat so many lemons cause I am so bitter.

Offline Lariemeeva

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1941 on: May 24, 2010, 05:57:57 pm »
Baladya: I know those simple stuff, I'm more concerned about the oxides of metals and Hydroxide...
Anyone?

Offline Vin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1942 on: May 24, 2010, 05:59:00 pm »
VIN thx , i don't kno what the heck is wrong with me today  >:(......

thx for baring with me (that's what our supervisor says whenever sh e reads the rules and regulations of ig exam ...so hilarious  , i keep laughin with my self most of the time she's readi cuz i memorixed it people :P)

LOL .. it happens  .. i know .. @your supervisor .. i wanna hear her ! :P

Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1943 on: May 24, 2010, 05:59:08 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.


Can anyone please explain this, I don't get this at all.  What's oxidation number?
Always willing to help!  8)
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Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1944 on: May 24, 2010, 05:59:12 pm »
    H    H                           H    H
     |    |        (steam)         |     |
H- C - C - H   ---------->    C = C    +   H2
     |    |        (>800 *C)      |     |
     H    H                           H     H

ETHANE                             ETHENE      HYDROGEN ;)


 

VIN , plz  look again at what u wrote ...ur talkin abt hydration ....while baladya is talkin abt crackin
Verily, in the remembrance of Allah do hearts find rest(13:28)

Please, Don't forget to Include GG in your Prayers =D

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1945 on: May 24, 2010, 05:59:22 pm »
Baladya: I know those simple stuff, I'm more concerned about the oxides of metals and Hydroxide...
Anyone?

i had the same porb , but u gotta do is that u memorized the solubility thingy list AND memorize the reactivity series ...ohh and understand them
Verily, in the remembrance of Allah do hearts find rest(13:28)

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Offline WARRIOR

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1946 on: May 24, 2010, 06:00:19 pm »
lol this has nothing to do with metals reacting with bases? ...
i copied the wrong question

opsi daizy
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But it ain't how hard you hit; it's about how hard you can get hit, and keep moving forward-Balboa

Offline Ghost Of Highbury

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1947 on: May 24, 2010, 06:00:42 pm »
Oxides and hydroxides..ummm, ok one thing to remember, learn the few basic colors of transition metals, like Fe(II)/Fe(iii) brown green stuff.

For example, nickel compounds are green, nickel being a transition metal.

Nickel hydroxide is also green...so u know wat im talking abt rite??

learn the colors of the metal compounds ...

copper - blue

iron - green /brown..etc. check the identification of cations table.
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Offline Lariemeeva

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1948 on: May 24, 2010, 06:01:43 pm »
Umm, link to O/N 2009 P1 please? :)

http://www.freeexampapers.us/IGCSE/Chemistry/CIE/2009%20Nov/0620_w09_qp_11.pdf

I don't understand Q23, why have they chosen 2 and 3 only? And Q13 why does OH- turn UI colourless?
« Last Edit: May 24, 2010, 06:03:39 pm by Lariemeeva »

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1949 on: May 24, 2010, 06:02:06 pm »
LOL .. it happens  .. i know .. @your supervisor .. i wanna hear her ! :P

lol ....trust u do  :P
Verily, in the remembrance of Allah do hearts find rest(13:28)

Please, Don't forget to Include GG in your Prayers =D