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Author Topic: Chemistry Help needed!:-(  (Read 12513 times)

Offline godfather93

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Re: Chemistry Help needed!:-(
« Reply #15 on: May 02, 2009, 06:09:14 pm »
normally, a pipette is only used for a few drops of a solution. A biuret is bigger and it can range from 10cm3 to 50 at the max. However whenever the quantity of the solution u r measuring is above 20cm3 it is advisable to put it in a measuring cylinder.
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #16 on: May 02, 2009, 07:53:29 pm »
@godfather
thanx for your help, itz really helpful... but are you sure about your answer ;) No offence!!! :)

@everyone
hey guyz i have one more question about fizzy drinks....
well there was a question in year nov 2001 last question ( i have attached the link)
so can you tell me from which topic was this question from?
and can anyone explain me the part (c)??
Thanks.
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #17 on: May 02, 2009, 08:08:15 pm »
i need the answer...plzzzzzzzzzzzzzz i have a test tomorrow :'(
help me :(
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Offline astarmathsandphysics

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Re: Chemistry Help needed!:-(
« Reply #18 on: May 02, 2009, 08:13:48 pm »
I will be able to answer this in 90 mins. Now i am on a mobile phone.
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #19 on: May 02, 2009, 08:57:55 pm »
okay no prob...i will wait
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Offline astarmathsandphysics

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Re: Chemistry Help needed!:-(
« Reply #20 on: May 02, 2009, 10:08:55 pm »
Fill a large basin full of water. Invert  another basin and completely submerge it in the first one so that it is full of water with no air bubbles. Now put the can of coke unside the upturned submerged 2nd basin and open it. The volume of gas releaSED is the answer. This can be found by using a calibrated beaker as the upturned 2nd container.
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Offline hyebyekadal

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Re: Chemistry Help needed!:-(
« Reply #21 on: May 03, 2009, 07:44:42 am »
astar i didnt get what u mean..
sorry and i looked up the ms and its  undecipherable!

can open under water to collect gas in graduated tube / m. cylinder (1)
filled with water (1), syringe = 0 (would not work) [2]
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Offline godfather93

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Re: Chemistry Help needed!:-(
« Reply #22 on: May 03, 2009, 08:23:22 am »
fill a beaker or a measuring cylinder with water to the brim. place it in another bowl full of water but turn it upside down inside the water without letting the air bubbles get in. submerge the can under the water and place it under the beaker/measuring cylinder (make sure no air bubbles get in and the beaker covers the top portion of the can only). open the can and when the gas bubbles are released, it is trapped by the measuring cylinder and gas replaces the water inside the measuring cylinder. take the reading of the empty space inside the measuring cylinder. that is the volume of the gas released. 
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #23 on: May 03, 2009, 11:14:38 am »
@astar & godfather
thanx guyz for your help that question really confused me especially the mark scheme.....
and if im not wrong i think this method is called the downward displacement of water...right?
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Offline godfather93

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Re: Chemistry Help needed!:-(
« Reply #24 on: May 03, 2009, 12:08:05 pm »
yes, good luck! ;)
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Offline hyebyekadal

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Re: Chemistry Help needed!:-(
« Reply #25 on: May 03, 2009, 12:51:32 pm »
Thank You but isnt CO2 heavier than air? so how the gas would still form on top of water??/ ( ok i hve a feeling i kinda mixed up concepts but ...)
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Offline godfather93

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Re: Chemistry Help needed!:-(
« Reply #26 on: May 03, 2009, 01:01:27 pm »
there is no air inside the beaker because it is filled with water
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #27 on: May 03, 2009, 02:55:14 pm »
hey guyz i have one more question....

Q: what is haxane layer colour??? well i dont know what is this word haxane layer means???
so plzz do answer me!!

Thank U!!! :)
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Offline twilight

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Re: Chemistry Help needed!:-(
« Reply #28 on: May 03, 2009, 03:01:12 pm »
Quote from: Naruto on May 03, 2009, 02:55:14 pm
hey guyz i have one more question....

Q: what is haxane layer colour??? well i dont know what is this word haxane layer means???
so plzz do answer me!!

Thank U!!! :)

the colour of hexane layer depends on the halogen produced during the reaction
check out these sites   
      http://www.miracosta.cc.ca.us/home/dlr/110exp10.htm
      http://jchemed.chem.wisc.edu/jcesoft/CCA/CCA3/MAIN/HALOGEN/PAGE1.HTM
« Last Edit: May 03, 2009, 03:02:59 pm by twilight »
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Offline Naruto

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Re: Chemistry Help needed!:-(
« Reply #29 on: May 03, 2009, 03:07:52 pm »
@ twilight
thanx that site really helped me!!! :)
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