Chemistry: Post your doubts here!

[Metanoia]

View attachment 54648

can someone please explain number 4? answer is A.

 

[alevelpleasebegood]

I saw this question in a reference boo.
Which species is deflected the least in an electric field?
A. 24Mg2+ B. 27Al3+ C. 16O2- D. 31P3-?
Why is the answer A, not D? A-D has the same number of electron, but D has the largest number of proton. Proton is deflected the least in an electric field isn't it?

 

[The Sarcastic Retard]

I saw this question in a reference boo.
Which species is deflected the least in an electric field?
A. 24Mg2+ B. 27Al3+ C. 16O2- D. 31P3-?
Why is the answer A, not D? A-D has the same number of electron, but D has the largest number of proton. Proton is deflected the least in an electric field isn't it?

It has highest m-e ratio..

 

[alevelpleasebegood]

It has highest m-e ratio..

so m/e ratio not only affects the deflection in magnetic field, but also electric field?

 

[The Sarcastic Retard]

so m/e ratio not only affects the deflection in magnetic field, but also electric field?

thats the only reason that clicked my brain..

 

[Arsha A]

Could someone please answer 2011 May/June Paper 12 Question 35. The mark scheme says the answer is A but the same question is in 2008 May/June(Question 36) and the answer there is C.

Thanks.

 

[Lola_sweet]

https://docs.google.com/viewerng/vi.../wp-content/uploads/2012/11/9701_s08_qp_1.pdf

Can someone show me the calculation for qs 6 ?
thank u

 

[ashcull14]

 

[The Sarcastic Retard]

https://docs.google.com/viewerng/vi.../wp-content/uploads/2012/11/9701_s08_qp_1.pdf

Can someone show me the calculation for qs 6 ?
thank u

m = 1g
mr = 18
n = 1/18
V = nRT/P
V = 1/18 * 8.32 * 596 / 101000 = 2.72dm^3 (the answer difference is due to change in dp)

 

[Lola_sweet]

m = 1g
mr = 18
n = 1/18
V = nRT/P
V = 1/18 * 8.32 * 596 / 101000 = 2.72dm^3 (the answer difference is due to change in dp)

wow im so dumb .-. i was doing such a long method :/
thanks bro

 

[alevelpleasebegood]

should

Could someone please answer 2011 May/June Paper 12 Question 35. The mark scheme says the answer is A but the same question is in 2008 May/June(Question 36) and the answer there is C.

Thanks.

Should be C, 2 and 3.
1 is obviously wrong, N is being reduced. The oxidation no. changed from +3 to 0.
2, and 3 are correct. NaClO is a bleach and AgCl (precipitate will form)

 

[princess Anu]

shoudn't it be 107? then how is it B?:s

 

[The Sarcastic Retard]

shoudn't it be 107? then how is it B?:sView attachment 54675

This is due to electronegativity of N > P. Detail explained here:¬
http://www.meritnation.com/ask-answ...mical-bonding-and-molecular-structure/1061393
Basically, answer is not 104 as well... Its just less then 109 degrees... so option here is give 104 so that is correct... if it was 107 given and 104 you should know 104 is the correct choice.. 90 and 104.. 90 is the correct and nearest degree..

 

[shazmina]

http://postimg.org/image/cdgwkai7x/full/
Help please!!!!!!!1

 

[princess Anu]

This is due to electronegativity of N > P. Detail explained here:¬
http://www.meritnation.com/ask-answ...mical-bonding-and-molecular-structure/1061393
Basically, answer is not 104 as well... Its just less then 109 degrees... so option here is give 104 so that is correct... if it was 107 given and 104 you should know 104 is the correct choice.. 90 and 104.. 90 is the correct and nearest degree..

You mean I should chose 104 instead 107? if 107 was given as an option ? :O

 

[shazmina]

The Sarcastic Retard qwertypoiu I need help in this question ...

Here i have posted the link for the question paper and my doubt is in question no 21 ....
I have even posted the explanation for Q21 which was answered previously .... My doubt is I don't get what they are trying to say in the part where i have highlighted ... so can one of you clarify it to me further.. Thanks in advance

https://docs.google.com/viewer?a=v&...sLm9yZ3x0ZWFjaGVyc3xneDoxYmI0OTYwOWIyZDRmNWVj

If the compound was an alkane and had no rings or double bonds, number of H atoms present = 2n+2 = 2(20)+2 = 42

Now, every time there're 2H less, you'll either have a double bond or a ring. The question states that there's one aldehyde (C=O) and 1 ring structure which has 1 C=C so this accounts for 6 missing Hydrogens, thereby leaving you with 8 missing Hydrogens.

8/2 = 4 Hydrogens in the aliphatic side chain.

However, total C=C are 5 because you have to include the C=C from the cyclohexene + cis formation hence A

 

[shazmina]

View attachment 54665

Dear, Image too small that i cant see even when i zoom it, its appearing blurred.

 

[The Sarcastic Retard]

The Sarcastic Retard qwertypoiu I need help in this question ...

Here i have posted the link for the question paper and my doubt is in question no 21 ....
I have even posted the explanation for Q21 which was answered previously .... My doubt is I don't get what they are trying to say in the part where i have highlighted ... so can one of you clarify it to me further.. Thanks in advance

https://docs.google.com/viewer?a=v&...sLm9yZ3x0ZWFjaGVyc3xneDoxYmI0OTYwOWIyZDRmNWVj

If the compound was an alkane and had no rings or double bonds, number of H atoms present = 2n+2 = 2(20)+2 = 42

Now, every time there're 2H less, you'll either have a double bond or a ring. The question states that there's one aldehyde (C=O) and 1 ring structure which has 1 C=C so this accounts for 6 missing Hydrogens, thereby leaving you with 8 missing Hydrogens.

8/2 = 4 Hydrogens in the aliphatic side chain.

However, total C=C are 5 because you have to include the C=C from the cyclohexene + cis formation hence A

Sorry, no time : https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-381#post-745892

 

[shazmina]

Sorry, no time : https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-381#post-745892

Its alright .. he has actually replied to the wrong question

 

[Furqan Azam]

Can someone please explain these:
MJ 14/11 Q8, 13, 34. Thank you.