Chemistry: Post your doubts here!

[periyasamy]

Which process could be used to calculate the bond energy for the covalent bond X-Y by dividing its ∆H by n?
A XYn(g)→X(g) + nY(g)
b 2XYn(g)→2XYn-1(g) + Y2(g)
C Y(g) + XYn-1(g)→XYn(g)
D nXY(g)→nX(g) +n/2 Y2(g)
Why is the answer a?
Help guys.Thanks a lot.

 

[periyasamy]

Guys ,just want to ask .For the question below option a is selected is it because it has something to do with the"in situ"preparation.Thanks a lot.

 

[Jinosupreme]

Guys ,just want to ask .For the question below option a is selected is it because it has something to do with the"in situ"preparation.Thanks a lot.

Answer is D as it is reaction between ketone and 24 DNPH, which is able to done without heating

 

[scouserlfc]

Which process could be used to calculate the bond energy for the covalent bond X-Y by dividing its ∆H by n?
A XYn(g)→X(g) + nY(g)
b 2XYn(g)→2XYn-1(g) + Y2(g)
C Y(g) + XYn-1(g)→XYn(g)
D nXY(g)→nX(g) +n/2 Y2(g)
Why is the answer a?
Help guys.Thanks a lot.

Remember what bond energy is,it is the energy released when a covalent bond of a gaseous molecule is broken to give gaseous atoms and not molecules or compounds or molecules. So in A only is this happening in the rest of the options ∆H not only contains the bond breaking energy but also bond formation so the resulting ∆H for B,C and D is lesser than the value of X----Y bond energy !
I hope you get it its pretty simple just try to understand and ask any question no matter how childish it is about this explanation !

 

[periyasamy]

Remember what bond energy is,it is the energy released when a covalent bond of a gaseous molecule is broken to give gaseous atoms and not molecules or compounds or molecules. So in A only is this happening in the rest of the options ∆H not only contains the bond breaking energy but also bond formation so the resulting ∆H for B,C and D is lesser than the value of X----Y bond energy !
I hope you get it its pretty simple just try to understand and ask any question no matter how childish it is about this explanation !

Thanks bro.

 

[periyasamy]

Answer is D as it is reaction between ketone and 24 DNPH, which is able to done without heating [/quote
Thanks boss,i understand it.But the answer i checked it n it shows a.

 

[periyasamy]

Answer is D as it is reaction between ketone and 24 DNPH, which is able to done without heating

Thanks boss,i understand it but sorry man,i checked the answer n it is A.

 

[Jinosupreme]

Thanks boss,i understand it but sorry man,i checked the answer n it is A.

Hmmmm, I guess it is said in book and notes, adding PCl5 or PI3 is not needed with heat and reflux. But other need high temp or heat in reflux, don't really know if this helps sorry :/

 

[periyasamy]

Hmmmm, I guess it is said in book and notes, adding PCl5 or PI3 is not needed with heat and reflux. But other need high temp or heat in reflux, don't really know if this helps sorry :/

I think u r right man.Thanks a lot.

 

[periyasamy]

my doubtzzView attachment 33040View attachment 33041View attachment 33042

Boss what is answer for question 23?

 

[Avik181]

can anyone explain no.6 and 7?

 

[Love Islam]

I want a proper definition for periodicity

And I want notes for Periodicity AND Group 2 & 7

Is there any one to help me out?

Thanks

 

[Jessie N.]

can anyone explain no.6 and 7?

XD

 

[Avik181]

XD

thabkyou!!!

 

[Abhi Mevawala]

Boss what is answer for question 23?

Ans is B
plzz do solve other doubtss xamz r near

 

[Abhi Mevawala]

Is the answer a?

can u xplain iit plzzz

 

[periyasamy]

Ans is B
plzz do solve other doubtss xamz r near

This one someone posted before.... we have 3 products.. ethene methane and propene...

if i mole is produced by cracking, then o.5% will be of ethene(as mentioned in the q) then 0.25 of propene and .25 of methane is produced... .25+.25+.5=1...

to convert .25 into proper fraction, we need to multiply it by 4 to bring it to a whole number... by doing this.. we will get 1 mole of propene, 1 mole of methane and 2 moles of ethene(.5*4).. no of Carbons now we have are 8 all together... so B is the answer...

 

[Abhi Mevawala]

ohh thnxx wat abt the other........

 

[x-gamer-x]

someone plz explain this

P1

Question :
Use of the Data Booklet is relevant to this question.
A washing powder contains sodium hydrogencarbonate, NaHCO3, as one of the ingredients. In a
titration, a solution containing 1.00 g of washing powder requires 7.15 cm3 of 0.100 mol dm–3
sulfuric acid for complete reaction. The sodium hydrogencarbonate is the only ingredient that
reacts with the acid.
What is the percentage by mass of sodium hydrogencarbonate in the washing powder?

Answer : 12

 

[*MK*skydiver :D]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_12.pdf

Q 11 you guys,It's been asked here for like 3 times and apparently it wasn't answered . can someone answer it for me ?
Can't think of an answer!


11 0.144 g of an aluminium compound X react with an excess of water, to produce a gas. This gas
burns completely in O2 to form H2O and 72 cm3
of CO2 only. The volume of CO2 was measured at
room temperature and pressure.

What could be the formula of X?
A Al 2C3 B Al 3C4 C Al 4C3 D Al 5C3