Chemistry: Post your doubts here!

[NokiaN95638]

Plz i need help with this question> can you please draw the hess's cycle.


Methanol may be synthesised from carbon monoxide and hydrogen. Relevant values of Hc
for this reaction are given in the table below.
compound
CO(g) –283
H2(g) –286
CH3OH(g) –726
(b) Use these values to calculate for the synthesis of methanol, using the following
equation. Include a sign in your answer.
CO(g) + 2H2(g) → CH3OH(g)

 

[jackandneenu]

if the value for electron affinity is not given in the question paper and if we need to knw its value in order to find the lattice energy................is there any way we can find it?'
is it given in the data booklet?

 

[NouranAyman]

hey please i have few questions in chemistry AS pleaseeeeee someone help me asap exam is on wednesday
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s07_qp_2.pdf which is may/june 2007 paper 2 btw, question 2(d) please for the first column , what is this is compound and what will be its product on oxidation??
Next is http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s08_qp_2.pdf which is may/june 2008 paper 2 , question 5 (a)ii and 5(e) what structural formula should we write can someone explain!!
and please some one post Good chemistry AS notes so i can revise from it tomorrow ((( and guys hows your preparation going?? pleaseee reply me anyone. Im freaked out

 

[PhyZac]

Assalamu Alikum WaRahamatulllah Wabarakatooh

Can anyone explain why is the answer of ( 3 ) (a) (ii) Is K potassium!

 

[jackandneenu]

ionic radius increases down the group and across the group it decreases because the atoms gets tightly bound to one another

 

[jackandneenu]

therefore the answer is potassium

 

[PhyZac]

jackandneenu Thank you so much, Jazak Allah Khairan.

 

[bamteck]

Chemistry sucks :'(

 

[TheCookieMonster]

Hi, so my Chemistry Paper 2 exam is on Wednesday and I'm having a serious problem. I've been doing some past papers and whenever I get to organic questions I just CAN'T seem to answer them. I know the syllabus, it's there in my brain but when I start doing organic questions I just sort of feel a blockage and I can't answer the question. When I attempt the questions, looking at all the structural formulas and things, I become completely overwhelmed and feel hopeless. I'm so worried now, I don't know what to do. I'm on the verge of panic, please help me!

 

[bamteck]

Hi, so my Chemistry Paper 2 exam is on Wednesday and I'm having a serious problem. I've been doing some past papers and whenever I get to organic questions I just CAN'T seem to answer them. I know the syllabus, it's there in my brain but when I start doing organic questions I just sort of feel a blockage and I can't answer the question. When I attempt the questions, looking at all the structural formulas and things, I become completely overwhelmed and feel hopeless. I'm so worried now, I don't know what to do. I'm on the verge of panic, please help me!

Same here

 

[tdk]

Hi everyone, do u have the Mark Scheme of AS Chemistry Paper 1 and paper 2 (9701/22) of May/June 2012? Especially I need the Mark Scheme of Paper 2 the Exam of which is to be held on November 7, 2012. Plzzzz help me. Thank u in advance.

 

[tdk]

Hi everyone, assalamoalaikum!!

To get things organized in a better way, I am making this thread. As othewise, some queries remain unanswered!

So post your CHEMISTRY doubts in this thread. InshaAllah members around will help you.

Any Chemistry related notes and links will be added here in this post. Feel free to provide the links to your notes around the forum, or any other websites!

Chemistry Notes:


http://www.chemguide.co.uk This is the website, which contains almost everything classified according to the syllabus.

Some links & Notes - by 'destined007'

Chemistry worksheets Link shared by hassam

Chemistry Application Booklet: Mistakes and Corrections!

Calculations for A level Chemistry, author E.N. Ramsden third edition ebook downloaAd.


Regards,
XPC Staff.

Could you please help me? I need the Mark Scheme of AS Chemistry Paper 2 (9701/22) of May/June 2012. The exam of this paper is on November 7, 2012. Thank you in advance.

 

[XPFMember]

Could you please help me? I need the Mark Scheme of AS Chemistry Paper 2 (9701/22) of May/June 2012. The exam of this paper is on November 7, 2012. Thank you in advance.

AsSalamoAlaikum Wr Wb!
http://olevel.sourceforge.net/papers/9701/

 

[tdk]

Hi everyone, assalamoalaikum!!

To get things organized in a better way, I am making this thread. As othewise, some queries remain unanswered!

So post your CHEMISTRY doubts in this thread. InshaAllah members around will help you.

Any Chemistry related notes and links will be added here in this post. Feel free to provide the links to your notes around the forum, or any other websites!

Chemistry Notes:


http://www.chemguide.co.uk This is the website, which contains almost everything classified according to the syllabus.

Some links & Notes - by 'destined007'

Chemistry worksheets Link shared by hassam

Chemistry Application Booklet: Mistakes and Corrections!

Calculations for A level Chemistry, author E.N. Ramsden third edition ebook download.


Regards,
XPC Staff.

Dear Bro, Assalamu Alaikum Wr Wb. I'm so happy getting ALL the MS that I can't thank u enough to express my gratitude. May Allah bless u.

 

[ijjukittu]

what will be the correct equation which represents bond energy of methane???
A: 1/4CH4 -------> 1/4 C + H
B: CH4------> C + 4H ( Ayub's book has mentioned this one )

 

[XPFMember]

what will be the correct equation which represents bond energy of methane???
A: 1/4CH4 -------> 1/4 C + H
B: CH4------> C + 4H ( Ayub's book has mentioned this one )

AsSalamoAlaikum Wr Wb..

B is correct as far as I know..

 

[XPFMember]

what will be the correct equation which represents bond energy of methane???
A: 1/4CH4 -------> 1/4 C + H
B: CH4------> C + 4H ( Ayub's book has mentioned this one )

AsSalamoAlaikum Wr Wb..!!

The bond energy is a measure of the amount of energy needed to break apart one mole of covalently bonded gases. So B is correct!

 

[NouranAyman]

Hi everyone, assalamoalaikum!!

To get things organized in a better way, I am making this thread. As othewise, some queries remain unanswered!

So post your CHEMISTRY doubts in this thread. InshaAllah members around will help you.

Any Chemistry related notes and links will be added here in this post. Feel free to provide the links to your notes around the forum, or any other websites!

Chemistry Notes:


http://www.chemguide.co.uk This is the website, which contains almost everything classified according to the syllabus.

Some links & Notes - by 'destined007'

Chemistry worksheets Link shared by hassam

Chemistry Application Booklet: Mistakes and Corrections!

Calculations for A level Chemistry, author E.N. Ramsden third edition ebook download.


Regards,
XPC Staff.

Al SAlam Alaikum! please i have few questions in chemistry AS pleaseeeeee help me asap exam is tomorrow
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s07_qp_2.pdf which is may/june 2007 paper 2 btw, question 2(d) please for the first column , what is this is compound and what will be its product on oxidation??
Next is http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s08_qp_2.pdf which is may/june 2008 paper 2 , question 5 (a)ii and 5(e) what structural formula should we write can someone explain!!
and please some one post Good chemistry AS notes so i can revise from it tomorrow ((( and guys hows your preparation going?? pleaseee reply me anyone. Im freaked out
One more question was how can we find the bond angle when they ask us H-C-H for example and they say suggest bond angles ​

 

[Amy Bloom]

can anyone explain me the meaning of more exothermic and/or less exothermic? give me values to support explanations please.

 

[M.Kabir Nawaz]

The energy to remove second mole of electron different does differ from removing second mole?