Author Topic: Chem doubts  (Read 4420 times)

Offline cashem'up

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Re: Chem doubts
« Reply #30 on: April 18, 2010, 01:15:08 pm »
Why is ethanoic acid a stronger acid in liquid ammonia than in aqueous solution?............. hey guys s03 question m confused........

Offline Saladin

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Re: Chem doubts
« Reply #31 on: April 18, 2010, 01:22:19 pm »
The strength of an acid is determined by how easily it can donate a proton.

Thus, when in liquid ammonia, there is stronger interaction between the NH3 molecules and the acid, than with water. This causes, protons to 'come out' easier than in water, as the internal bonding forces are more strongly overcome.

Thus in ammonia, it has a greater ability to donate a proton.

Offline cashem'up

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Re: Chem doubts
« Reply #32 on: April 18, 2010, 02:22:34 pm »
thanks.............yea that makes sense so yes it will more easily dissociate..........however u cant check this wid indicator can u ...............to deternmne its strenght

Offline 3ishakay

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Re: Chem doubts
« Reply #33 on: April 18, 2010, 08:45:08 pm »
can any1 help me out wiv

mj-08 ppr 1
question numbr 6 !?!?

Thanks

nid404

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Re: Chem doubts
« Reply #34 on: April 19, 2010, 06:34:17 am »

1g= 1/18 mole

1 mole=24dm3 at 298K and 1atm
but temp is 596 K...2 times

so 1 moles at 596K occupies 48dm3
1/18 X48= 2.67

C is the ans

Offline Saladin

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Re: Chem doubts
« Reply #35 on: April 19, 2010, 06:39:15 am »
thanks.............yea that makes sense so yes it will more easily dissociate..........however u cant check this wid indicator can u ...............to deternmne its strenght

Yes, that reactions with this substance will simply be more vigorous.

Offline The SMA

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Re: Chem doubts
« Reply #36 on: April 19, 2010, 07:37:13 am »
hi  :) can someone explain to me what is permanent dipole, induced dipole interaction please? and there's one more, dipole-dipole interaction, if i'm not mistaken. can someone explain the differences too? i'm so confused when it comes to this T.T

Offline tmisterr

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Re: Chem doubts
« Reply #37 on: April 19, 2010, 11:07:55 am »

ya, sure ill sent them as soon as i scan dem 4 u :)

nd 4 Q 31, how do we know if the bars represent isotopes or atoms ????????
6 The density of ice is 1.00 g cm–3.

cud u also xplain this Q ......

Q>What is the volume of steam produced when 1.00 cm3 of ice is heated to 323 °C (596 K) at a
pressure of one atmosphere (101 kPa)?

[1 mol of a gas occupies 24.0 dm3 at 25 °C (298 K) and one atmosphere.]
A. 0.267 dm3  B. 1.33 dm3  C. 2.67 dm3   D. 48.0 dm3


thanx sooo much for da help, By the way all ur answers r riteeee!!!





hey, sorry for the late reply, been a bit busy. nid already answered this question for you :). But for question 31 i don't know how to explain, it's just a matter of observing the question let me give a try. from the graph, the masses of each bar increasing by 32.1. As you know, the Ar of sulphur is 32.1 (one mole of sulphur atoms). If two sulphur atoms are to covalently bond forming a diatomic molecule, then you add another 32.1 to get the Mr of a diatomic sulphur molecule S2 (64.2) and you keep of adding till you get to the octa-atomic S8 which has an Mr of 256.8. so each bar is representing a different molecule(not atom), the first is mono-atomic the second diatomic the third tri-atomic the fourth tetra-atomic....u get the point, so they cannot be isotopes.

Thanks, much appreciated, tell me when they are ready.

Offline sweetie

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Re: Chem doubts
« Reply #38 on: April 19, 2010, 01:06:49 pm »
its alrite, never mind  8)

ya, got ur point , Thank You :D

sure , i'll  inform u when dey r ready  :)

Offline 3ishakay

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Re: Chem doubts
« Reply #39 on: April 19, 2010, 01:14:10 pm »
1g= 1/18 mole

1 mole=24dm3 at 298K and 1atm
but temp is 596 K...2 times

so 1 moles at 596K occupies 48dm3
1/18 X48= 2.67

C is the ans


Thanks =D


Offline cashem'up

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Re: Chem doubts
« Reply #40 on: April 19, 2010, 04:15:07 pm »
Use of the Data Booklet is relevant to this question.
Which properties would be expected from radium, 88Ra, or its compounds?
1 Radium carbonate decomposes only at a very high temperature.
2 Radium hydroxide is very insoluble.
3 Radium does not react with cold water.

hey guys a doubt the answer to this is only 1 is correct but shouldnt 2 also be correct

Offline Saladin

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Re: Chem doubts
« Reply #41 on: April 19, 2010, 04:22:49 pm »
Radium hydroxide is soluble, because it is lower down in group 2, and so the bond will not be strong. Genereally, the higher up group 2 u go, the more insoluble stuff gets. Becuase the lower you go the weaker the cation becomes.

Anyways, the reason why 1 is correct is because, the lower down you go the stronger carbonates get, why?? explained here: Thermal stability of carbonates and nitrates