Chemistry: Post your doubts here!

[Alice123]

Construct the balanced equation for the reaction between N2 and H2. 120-96 kg of H2 is used. Use mole ratios.

in that case 8 moles of N2 will react with 24 moles of H2 and 16 moles of NH3 are produced....
so mass of NH3 wud be 16* Mr of NH3 ie 272 :/ please help me out

 

[Dr.MMM]

Thank you so much

 

[h4rriet]

Can you do it for me ?

 

[cute97]

i think we will have products ethanoic acid and propanol

ummm noo i think sodium ethanoate and propanol i tried it and i got correct answer cz in the ques they used an alkali so salt of the acid is formed instead of an acid COONa

 

[kiran11]

B's dipole is 6 multiplied by the dipole of C-H, whereas C's dipole is 2 multiplied by the dipole of C-Cl.

i am sorry but i still have confusion whr did the 6 and 2 came from to multiply with c-h nad c-cl

 

[Aries_95]

Can you do it for me ?

apart form drawing the Hess's cycle, try using this method:
C3H6O+4O2---->3CO2+3H2O
Enthalpy change of combustion of propanone is the enthalpy change of reaction. and the enthal of formation of an element is always zero.
(-1786)+(Enthalpy of formation of propanone)= (3x enthalpy of combustion of C)+ (3x enthalpy of H2)
(-1786)+(X)= (3x-394)+(3x-286)
(-1786)+X=(-1182)+(-858)
(-1786)+X=-2040
X=-254 kj/mol
Answer is C.
Plz tell me is this answer right?

 

[kiran11]

ummm noo i think sodium ethanoate and propanol i tried it and i got correct answer cz in the ques they used an alkali so salt of the acid is formed instead of an acid COONa

i didnt see NaOH, sorry :-s

 

[darkxangel]

apart form drawing the Hess's cycle, try using this method:
C3H6O+4O2---->3CO2+3H2O
Enthalpy change of combustion of propanone is the enthalpy change of reaction. and the enthal of formation of an element is always zero.
(-1786)+(Enthalpy of formation of propanone)= (3x enthalpy of combustion of C)+ (3x enthalpy of H2)
(-1786)+(X)= (3x-394)+(3x-286)
(-1786)+X=(-1182)+(-858)
(-1786)+X=-2040
X=-254 kj/mol
Answer is C.
Plz tell me is this answer right?

Yes, the answer is C and thankyou

 

[Dr.MMM]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf Q28?

 

[darkxangel]

Thankkks

 

[Aries_95]

Yes, the answer is C and thankyou

Welcome
Hope you understand

 

[h4rriet]

i am sorry but i still have confusion whr did the 6 and 2 came from to multiply with c-h nad c-cl

2 C-Cl bonds and 6 C-H bonds (because there are 2 CH3 groups and each group contains 3 C-H bonds; draw a displayed formula if it still isn't clear).

 

[kiran11]

2 C-Cl bonds and 6 C-H bonds (because there are 2 CH3 groups and each group contains 3 C-H bonds; draw a displayed formula if it still isn't clear).

ok thank u i got it now. thank u so much!

 

[cute97]

ANYONE PLS
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_11.pdf
Q4, Q17,Q23
thanks in advance plz answer

 

[strangerss]

how does NF3 have 6 bonding pair ?

Bonding pair or you mean bonding electrons?

 

[Aries_95]

ANYONE PLS
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_11.pdf
Q4, Q17,Q23
thanks in advance plz answer

Q.4:
N2+O2--->2NO
180+(-994)+(-494)= 2X
X=655 hence A.

 

[HubbaBubba]

I have a couple of questions I don't really understand, could anybody help?

 

[darkxangel]

Two moles of compound P were placed in a vessel. The compound P was partly decomposed by heating. A dynamic equilibrium between chemicals P, Q and R was established.
At equilibrium, x mol of R were present and the total number of moles present was (2 + x).
What is the equation for this equilibrium?
A P 2Q + R
B 2P 2Q + R
C 2P Q + R
D 2P Q + 2R
I need help in this question as well !

 

[h4rriet]

in that case 8 moles of N2 will react with 24 moles of H2 and 16 moles of NH3 are produced....
so mass of NH3 wud be 16* Mr of NH3 ie 272 :/ please help me out

I'm trying to work it out but I'm not getting any of the options! Wait a bit, I'll post up the answer in a while, after I figure it out.

 

[strangerss]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_11.pdf can some one explain Q11 please??