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Author Topic: Chemistry Help!  (Read 6796 times)

Offline cockyxrocker

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Chemistry Help!
« on: April 25, 2009, 01:44:48 pm »
A reaction occured which can be represented by the following equation
Steam + magnesium ---> magnesium oxide + gas v

1.What was the appearance of the magnesium
(i)before the experiment?
(ii)after the experiment?
(iii)Suggest an identity for gas v
(iv)Suggest a test for gas v
(v)Suggest why the tube containing the magnesium ofen cracks on cooling.

I only need help with the last part...dont know how to exactly answer it.
Thanks in advance ^^
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Offline twilight

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Re: Chemistry Help!
« Reply #1 on: April 25, 2009, 01:49:30 pm »
look the reaction is highly exothermic .. so this heats the test tube a lot and the test tube expands ( solids usually expand on heating)
when u cool it suddenly (like by putting it in cold water or even normal tap water) it contract back suddenly .. so it cracks ..
especially if a part of the tube is cooled before the other

hope this helps  ;)
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Offline cockyxrocker

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Re: Chemistry Help!
« Reply #2 on: April 25, 2009, 01:52:48 pm »
Thanks  :D
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Offline Naruto

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Re: Chemistry Help!
« Reply #3 on: April 25, 2009, 09:24:13 pm »
hey
Can anyone tell me which topics should i prepare for my Chemistry paper6 ??? i mean the name of the topics. And should i prepare the whole book for the paper 6 or just few topics will be enough???
Plzzz help me thanks.
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Offline sweetsh

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Re: Chemistry Help!
« Reply #4 on: April 25, 2009, 09:29:24 pm »
paper 6 chemistry is pretty easy.Pay attention to the laboratory equipments and such things.Ofcourse you know how tomeasure things and draw graphs..In addition to the acid&bases table and the experiments plans which come the last page of the paper.. Solve as much past papers as you can types of questions are always the same..
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Offline Naruto

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Re: Chemistry Help!
« Reply #5 on: April 25, 2009, 09:32:16 pm »
Thanks :)
By the way can u tell me which chemistry book are you using?
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Offline sweetsh

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Re: Chemistry Help!
« Reply #6 on: April 25, 2009, 09:35:15 pm »
actually I dont use my book mainly..i use my teacher's notes..or you can say book! But anyway i'll post the book's name by tomorrow.
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Offline hyebyekadal

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Re: Chemistry Help!
« Reply #7 on: April 26, 2009, 08:17:50 am »
oya in which paper does the above question appear in? its so un-IGCSE-ish rite? i mean about the cracking of the glass.. isn't that like physics?
just asking! oya can anyone post a good link or something wer u can get a list of eperiments that u need to now? thanks!
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Offline astarmathsandphysics

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Re: Chemistry Help!
« Reply #8 on: April 26, 2009, 08:19:21 am »
I think it is physicssy too.
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Offline Naruto

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Re: Chemistry Help!
« Reply #9 on: April 26, 2009, 05:07:28 pm »

Q:In Sweden, caesium-137 built up in small plants called lichen. These plants were eaten by reindeers and gave rise to radioactive meat.
(i) If radioactive caesium was reacted with the chlorine, would you expect the caesium chloride produced to be radioactive? Explain your answer.

I dont knw how to exactly answer this question  ??? Can anyone tell me how to answer this question ???
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Offline sweetsh

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Re: Chemistry Help!
« Reply #10 on: April 26, 2009, 05:11:15 pm »
Please inform me with your Chemistry subject code.
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Offline Naruto

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Re: Chemistry Help!
« Reply #11 on: April 26, 2009, 05:17:29 pm »
This is the question from IGCSE past papers... the year is 1992... thats why i dont knw the answer :(
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Offline astarmathsandphysics

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Re: Chemistry Help!
« Reply #12 on: April 26, 2009, 05:24:38 pm »
Yes since radioaactivity is a property of the atom not the molecule
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Offline hyebyekadal

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Re: Chemistry Help!
« Reply #13 on: April 26, 2009, 05:25:05 pm »
Yes it is radioactive because radioactivity is physical process that takes place at  the nucleus of atoms. The caesium bonding with the chlorine doesn't affect the nucleus and it'd still be radioactive.
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Offline twilight

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Re: Chemistry Help!
« Reply #14 on: April 26, 2009, 05:29:10 pm »
yeah i think its going to b radio active because radioactivity is because of the different neutron number .. it affects the nucleus
so when caesium reacts with chlorine online electrons are involved .. the nucleus is not affected so it remains radioactive
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