Author Topic: Chemistry ppr 1 doubts  (Read 1023 times)

Offline moon

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Chemistry ppr 1 doubts
« on: June 02, 2010, 11:01:54 pm »
can somebody help me in solving ppr1 June. 07 Q16,18,34,39 appreciate ur help.

nid404

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Re: Chemistry ppr 1 doubts
« Reply #1 on: June 03, 2010, 06:46:44 am »
can somebody help me in solving ppr1 June. 07 Q16,18,34,39 appreciate ur help.

16) As the size of the atom increases down group 7, the electronegativity decreases and the bonds are held less stongly. Bond enthalpy decreases. Hence C

18) The gas given off will be ammonia. The only compound that can give off  ammonia is D(check the fornula)

34) Rise in temp, increases the rate of forward reaction...implies delta h is positive. Hence only 1

39) There are 3 chiral carbons. 1 is wrong.  2 is right because the alkene could form between any of the  Carbon atom...either the one to the right of OH or to the left. 3 is right cause it's a secondary alcohol and will be oxidised to ketone on reacting with Cr2O7...Cr changes color from orange Cr+6 to green Cr+3

Offline moon

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Re: Chemistry ppr 1 doubts
« Reply #2 on: June 03, 2010, 05:49:47 pm »
Thanks a lot nid. i really appreciate your great help.Thanks once again :)

nid404

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Re: Chemistry ppr 1 doubts
« Reply #3 on: June 03, 2010, 05:50:24 pm »
Anytime  :)

Offline sweetie

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Re: Chemistry ppr 1 doubts
« Reply #4 on: June 03, 2010, 08:15:28 pm »
need help in Q 10,23,39 of nov04

thanx 4 any help!

Offline thecandydoll

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Re: Chemistry ppr 1 doubts
« Reply #5 on: June 04, 2010, 06:44:50 am »
O/N 2007 PAPER 1 Q1/

Offline thecandydoll

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Re: Chemistry ppr 1 doubts
« Reply #6 on: June 04, 2010, 06:58:18 am »
What is formed when magnesium and barium nitrate reacts?

Offline girl_92

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Re: Chemistry ppr 1 doubts
« Reply #7 on: June 05, 2010, 04:34:08 pm »
What is formed when magnesium and barium nitrate reacts?
magnesium nitrate will be formed displacement reaction
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline Chingoo

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Re: Chemistry ppr 1 doubts
« Reply #8 on: June 05, 2010, 05:03:56 pm »
magnesium nitrate will be formed displacement reaction

No. There will be no reaction since Barium is more reactive than Magnesium in the Reactivity Series and cannot be displaced from it's compound by Magnesium.
All that is on earth will perish:
But will abide (forever) the Face of thy Lord--full of Majesty, Bounty & Honor.
Then which of the favors of your Lord will ye deny?


Qura'n, Chapter 55: The Beneficent, Verses 26-28

Offline girl_92

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Re: Chemistry ppr 1 doubts
« Reply #9 on: June 05, 2010, 05:13:46 pm »
No. There will be no reaction since Barium is more reactive than Magnesium in the Reactivity Series and cannot be displaced from it's compound by Magnesium.
oops sorry i didnt read properly
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u