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Author Topic: Chemistry Help HERE ONLY !!  (Read 107379 times)

Offline islu_jf

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Re: Chemistry Help HERE ONLY !!
« Reply #525 on: May 30, 2009, 07:57:51 pm »
how can u calculate the mass of one mole of C8 alcohol. ???????
plz help
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Offline SGVaibhav

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Re: Chemistry Help HERE ONLY !!
« Reply #526 on: May 30, 2009, 08:00:28 pm »
HELP REQUIRED EXPERT PEOPLE!

Please solve Question 5 of  Chem P3      May/June 2002.
No guesses please, because we cannot find a relevant markscheme.
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Offline godfather93

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Re: Chemistry Help HERE ONLY !!
« Reply #527 on: May 30, 2009, 08:07:47 pm »
liquids do not fill up the container because there are weak attractions between the molecules that prevent the molecules from escaping. the particles do not have enough kinetic energy to break these inter molecular forces. whereas a gas fills up the container because there is virtually no attraction between the particles, so they can move in any direction they want. gases show the property of diffusion.
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Offline ig_kid

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Re: Chemistry Help HERE ONLY !!
« Reply #528 on: May 30, 2009, 08:11:49 pm »
Quote from: godfather93 on May 30, 2009, 07:39:41 pm
what is stochiochemitry or something like that?
Stochiochemitry is something that has to do with moles.
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Offline crypsAnity

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Re: Chemistry Help HERE ONLY !!
« Reply #529 on: May 30, 2009, 08:17:52 pm »
Quote from: nid404 on May 30, 2009, 06:07:28 pm
Quote from: ManaH on May 30, 2009, 05:52:10 pm
hey,
umm can some clearify my doubts:)
1)
Q)descirbe the polltuion prblems caused by the disposal of polymer in ther landfills sites n by buring?
2)(c) Each tablet contains the same number of moles of CaCO3 and MgCO3. One tablet
reacted with excess hydrochloric acid to produce 0.24 dm3 of carbon dioxide at r.t.p.
CaCO3 + 2HCl ? CaCl2 + CO2 + H2O
MgCO3 + 2HCl ? MgCl2 + CO2 + H2O
(i) Calculate how many moles of CaCO3 there are in one tablet.
number of moles CO2 = ..............(0.01)
number of moles of CaCO3 and MgCO3 = ..............(0.01)
number of moles of CaCO3 = ..............(0.01)

(ii) Calculate the volume of hydrochloric acid, 1.0 mol /dm3, needed to react with one
tablet.
number of moles of CaCO3 and MgCO3 in one tablet = ..............(0.02)
Use your answer to (c)(i).
number of moles of HCl needed to react with one tablet = ..............(0.02)
volume of hydrochloric acid, 1.0 mol /dm3, needed to
react with one tablet ..............(0.02)
he brackets are my anser cans ome one help?:)

1. in landfill sites they cause visible pollution and burning releases toxic gases. remember to write toxic or poisonous not harmful
2.i)correct
ii)correct

eeee... toxic for real? .. dang it.. n thot i was a chem genius lol .. ahaha ..
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There is simply more to life than being cool .. =]

Offline SGVaibhav

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Re: Chemistry Help HERE ONLY !!
« Reply #530 on: May 30, 2009, 08:19:56 pm »
PLEASE ANSWER THE QUESTION ASKED UP, AS IF YOU ARE WRITING MODEL ANSWERS BY CIE.
Thanks

And yeah, i found the best way to write ionic bond [found from model answers]
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Offline islu_jf

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Re: Chemistry Help HERE ONLY !!
« Reply #531 on: May 30, 2009, 08:21:05 pm »
how can u calculate the mass of one mole of C8 alcohol. Huh?Huh??
plz help
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Offline godfather93

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Re: Chemistry Help HERE ONLY !!
« Reply #532 on: May 30, 2009, 08:28:14 pm »
Quote from: islu_jf on May 30, 2009, 08:21:05 pm
how can u calculate the mass of one mole of C8 alcohol. Huh?Huh??
plz help

the formula of C8 alcohol is C8H17OH
the molar mass is (12x8)+(17x1)+16+1 = 130
the no of moles is 1
the mass is no. of moles x molar mass = 130g
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Offline islu_jf

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Re: Chemistry Help HERE ONLY !!
« Reply #533 on: May 30, 2009, 08:51:05 pm »
ohhhhhhhhhhhhhhh  :D
tanx. + rep.
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Offline emi

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Re: Chemistry Help HERE ONLY !!
« Reply #534 on: May 30, 2009, 08:58:31 pm »
can some one please solve paper3  O/N 2002 Q1 part (iv)  ??  please and state how u did it ?

and also the same year paper 3 Q3 part (f) all parts  and explain how u did it ??? please
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Offline evilzurg307

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Re: Chemistry Help HERE ONLY !!
« Reply #535 on: May 30, 2009, 08:59:28 pm »
Can any one make a mnemonic for the reactivity series containing:
K
Na
Ca
Mg
Al
C
Zn
Fe
Pb
H
Cu
Hg
Ag
Pt
Au

If you already know one please tell im having a lot of difficulty remembering this one.

I cant memorize the action of heat on Hydroxides, Nitrates and Carbonates too.

Im not really the mug up type lol
Please help!
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Offline evilzurg307

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Re: Chemistry Help HERE ONLY !!
« Reply #536 on: May 30, 2009, 09:07:17 pm »
Quote from: ManaH on May 30, 2009, 06:22:28 pm

Omg i am so proud of myslef i finally got stichromatery*dances arund the house*
about the harmful ya i know i read the xmainer comment sayin gits not harmful write
TOXIC/ Posioniustnx anyways:)
rep (+)

Even I did that when i got the concept of stoichiometry
lol
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Offline SGVaibhav

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Re: Chemistry Help HERE ONLY !!
« Reply #537 on: May 30, 2009, 09:10:39 pm »
Quote
Quote from: sgvaibhav on May 30, 2009, 08:00:28 pm
HELP REQUIRED EXPERT PEOPLE!

Please solve Question 5 of  Chem P3      May/June 2002.
No guesses please, because we cannot find a relevant markscheme.
Quote
PLEASE ANSWER THE QUESTION ASKED UP, AS IF YOU ARE WRITING MODEL ANSWERS BY CIE.
Thanks

Waiting....
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Offline SGVaibhav

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Re: Chemistry Help HERE ONLY !!
« Reply #538 on: May 30, 2009, 09:11:24 pm »
i did almost 66 posts today
 too much
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Offline ig_kid

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Re: Chemistry Help HERE ONLY !!
« Reply #539 on: May 30, 2009, 09:12:06 pm »
Quote from: sgvaibhav on May 30, 2009, 08:00:28 pm
HELP REQUIRED EXPERT PEOPLE!

Please solve Question 5 of  Chem P3      May/June 2002.
No guesses please, because we cannot find a relevant markscheme.

5) a-The gas particles hv more energy and move farther apart and move faster so they don't stay next to each other. The liquid particles have less energy and move less so they stay next to each other but the particles are still moving

b-i)gas volume and ratio of gas in air
   ii)Carbon dioxide, because it is less dense than sulpher dioxide and has a lower Mr. It also has a higher ratio in air.

c-i)110cm3
   ii)14.4cm3
   ii)54.4cm3

d- 9/54=0.167mol
    0.5mol
    0.5*18= 9g
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