Chemistry: Post your doubts here!

[Xaptor16]

CH4(g) + 2O2(g) -------> CO2(g) + 2H2O(l)
C2H6(g) + 3.5O2(g) --------> 2CO2(g) + 3H2O(l)
Residual gas is CO2 which is absorbed by KOH(aq)
CO2(g) + OH-(aq) ---------> CO3(-2)(aq) + H2O(l)
Volume of CO2 produced by CH4 and C2H6 is 10 and 20 cm^3 respectively, total volume of CO2 produced = 30 cm^3

Eqn 1 : Sn2+ = Sn4+ + 2e-
Eqn 2 : MnO4- + 8H+ + 5e- = Mn2+ + 4H2O
These equations are available in data booklet : http://www.cie.org.uk/images/164870-2016-specimen-data-booklet.pdf
Balance the number of electrons, SHOULD BE EQUAL IN BOTH THE EQN.
Eqn 1 : 5Sn2+ = 5Sn4+ + 10e-
Eqn 2 : 2MnO4- + 16H+ + 10e- = 2Mn2+ + 8H2O
Add Eqn 1 with Eqn 2 = 5Sn2+ + 2MnO4- + 16H+ = 5Sn4+ + 2Mn2+ + 8H2O
Ignore liquids, we are just taking ions into account.
2moles of MnO4- reacts with 5moles of Sn2+
2 Mn---> 5 Sn
0.4 Mn <- 1 Sn
Hence, 9.5/190 * 0.4 = 0.02mol

thank you so very much!!

 

[psychiatrist]

thank you so very much!!

http://kinggsofchemistry.weebly.com/uploads/2/7/1/9/27197677/atomic_structure.pdf
Q4,6,17,18,27. ASAP.
Metanoia asadalam The Sarcastic Retard

 

[Metanoia]

Try to type out the corresponding answers next time.

Q4. The N has a -3 charge. So it has 10 electrons.

Q6. (1/5 x 10) + (4/5 x 11) = 10.8

Q17. Outer shell 7s2 7p6, total 8 outer electrons. Group 0.

Q18. EDITED: ORIGINAL EXPLANATION IS WRONG.

Q27. From data booklet. Tc has 43 protons. In the question, the information is that it has 99 nucleons (protons + neutrons).

 

[Metanoia]

Q what will be the result of oxidising this compound with Hot conc K2cR2O7.
Acc to me there should be no change!! any help will be appreciated!

Did the question ask for hot conc K2Cr2O7 or hot dilute K2Cr2O7 ?

 

[princess Anu]

I don't know the question

My friend just asked me what this compound resulted in under hot conc k2cr207

 

[Studydayandnight]

How do we figure out the bond angle in this case?

 

[psychiatrist]

Try to type out the corresponding answers next time.

Q4. The N has a -3 charge. So it has 10 electrons.

Q6. (1/5 x 10) + (4/5 x 11) = 10.8

Q17. Outer shell 7s2 7p6, total 8 outer electrons. Group 0.

Q18. Easiest is to use the data booklet and look at IE of the four options , IE 2 > IE 1 > IE3

Q27. From data booklet. Tc has 43 protons. In the question, the information is that it has 99 nucleons (protons + neutrons).

Q6 : From where did 1/5 and 4/5 came?

Q17,18 : I dont understand.

Q27 : IDK how statement 1 is correct.

Ty.

 

[The Sarcastic Retard]

How do we figure out the bond angle in this case?

3 sigma bond ; sp2 hybridization = 120 degrees.
You should know
sp = 180
sp2 = 120
sp3 = 109.5

 

[Studydayandnight]

How do I know what the damn cyclic compound looks like? :'(

I am so DONE with chemistry. -_-

 

[Studydayandnight]

3 sigma bond ; sp2 hybridization = 120 degrees.
You should know
sp = 180
sp2 = 120
sp3 = 109.5

Oh, riiiight. There is just so much to remember!! And I forget after two days, the little details.

Thanks for your help though, if I somehow manage to get an A, it'll be because of you guys helping me out here

 

[The Sarcastic Retard]

Oh, riiiight. There is just so much to remember!! And I forget after two days, the little details.

Thanks for your help though, if I somehow manage to get an A, it'll be because of you guys helping me out here

Surely, A isn't impossible if u work smartly.

 

[Metanoia]

I don't know the question

My friend just asked me what this compound resulted in under hot conc k2cr207

The truth is data of hot K2Cr2O7 on C=C is not readily available.

So I am inclined to assume that it does not affect the C=C double bond unless some other info says otherwise.

I doubt cambridge would require students to be aware of the answers unless the reaction is well-established.

 

[The Sarcastic Retard]

How do I know what the damn cyclic compound looks like? :'(

I am so DONE with chemistry. -_-

Apply the knowledge that C can form 4 bonds, O can 2 and H can 1 it will look like this :

 

[Metanoia]

Q6 : From where did 1/5 and 4/5 came?

Q17,18 : I dont understand.

Q27 : IDK how statement 1 is correct.

Ty.

Q6. From the relative abundance chart. Ratio of Isotope-10 : Isotope - 11 is 1:4

Q17. I saw the wrong question and explained for Q14.
Use your data booklet and locate the elements that represent the four options. Fill them in here before I explain further.
A.
B.
C.
D.

Q18. Again, us your data booklet write down the 1st, 2nd and 3rd IE of four options. Fill them in here before I explain further.
C
N
F
Na

Q27. From your understanding, how many protons, electrons and neutrons does Tc have?

 

[The Sarcastic Retard]

Apply the knowledge that C can form 4 bonds, O can 2 and H can 1 it will look like this :

Metanoia m i correct? why does ms says we have to draw two diagrams? :/ and y there is no 2 oxygen attached in 1st diagram in ms

 

[Metanoia]

Metanoia m i correct? why does ms says we have to draw two diagrams? :/ and y there is no 2 oxygen attached in 1st diagram in ms

I think to be safe, I would want to see the rest of the original question to see the context.

 

[The Sarcastic Retard]

I think to be safe, I would want to see the rest of the original question to see the context.

http://onlineexamhelp.com/wp-content/uploads/2014/02/9701_w13_qp_22.pdf
Q4

 

[Metanoia]

Metanoia m i correct? why does ms says we have to draw two diagrams? :/ and y there is no 2 oxygen attached in 1st diagram in ms

Drawing the 2nd diagram will get you the two marks.

If students only managed to draw the first diagram (incomplete) , they will get 1 out of the max 2 marks.

 

[The Sarcastic Retard]

Drawing the 2nd diagram will get you the two marks.

If students only managed to draw the first diagram (incomplete) , they will get 1 out of the max 2 marks.

Hey Electron affinity is in As level?
What if I draw like this :

 

[Metanoia]

Hey Electron affinity is in As level?
What if I draw like this :

Your diagram is fine. Its the same as the marking scheme.