Chemistry: Post your doubts here!

[Metanoia]

View attachment 58766
I don't understand why there will be no change in the beaker with Fe3+/Fe2+
Surely adding SO4- to there will also affect the equilibrium due to the common ion effect...
So why no change??
Metanoia

hmm..this question was addressed here.

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-733#post-942233

 

[Metanoia]

View attachment 58764
How to find order wrt H+ ??
I found the others as 1 but idk how to do it for H+
Metanoia

order with respect to [CH3CHO] is 1
order with respect to [CH3OH] is 1

You would need answers to part a and b to find order with respect with H+, compare any two experiments and also sub in orders with respect to [CH3CHO] and [CH3OH].

e.g
Experiment 1 and 4

 

[Metanoia]

Can anyone please explain the VSEPR (valence shell electron pair repulsion) theory that we are supposed to know for chapter 3 (chemical bonding) in AS Chem? Also, I do not understand the rules. I mean, if a rule states that if there are 4 pairs of electrons (no lone pairs) around the central atom then the molecule is said to be tetrahedral with a bond angle of 109.5 degrees, however, that is not the case with a CO2 molecule which I don't seem to get as to why it is linear and not tetrahedral even though it has 4 pairs of electrons around the Carbon atom. If anyone could explain or direct me to a link online which explains it clearly with all the rules that we are supposed to know to determine the shape that would be really helpful.

Thanks.

Rather than view it in terms of "electron pairs", it is more correct to view it as "electron groups", so there are two electron groups around the carbon atom in CO2.

I did a few videos on molecular shapes, hope they might be useful to clear things up for you.

 

[The Sarcastic Retard]

hmm..this question was addressed here.

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-733#post-942233

I dont get it.

 

[The Sarcastic Retard]

Part (ii)

 

[leenz98]

Can someone please explain as many questions as possible from amongst mcq no 12,17,19,20,22,26,28,29 of 9701 MJ 2011 paper 12. Thanks in advance.

 

[Metanoia]

I dont get it.

Perhaps you can explain why you think the equilibrium on the left cell would change if sulfates was added, using any equilibrium equations you think is relevant.

 

[leenz98]

Perhaps you can explain why you think the equilibrium on the left cell would change if sulfates was added, using any equilibrium equations you think is relevant.

Which question are you referring to?

 

[Metanoia]

Which question are you referring to?

I'm referring to the reply by The Sarcastic Retard.

For your queries, you can click on the link on my signature "YouTube Videos for solutions to 9701 MCQ"

 

[leenz98]

I'm referring to the reply by The Sarcastic Retard.

For your queries, you can click on the link on my signature "YouTube Videos for solutions to 9701 MCQ"

I cant open this link.

 

[Metanoia]

I cant open this link.

Click on the heading of the video, it would direct you to youtube and you can look at the other videos.

 

[nehaoscar]

View attachment 58773
Part (ii)

Try using these two equations
so overall equation is:
Cr2O72- + 14H+ + 6Cr2+ ----> 8Cr3+ 7H2O
Ecell = 1.33 + 0.41
= 1.74V

 

[nehaoscar]

hmm..this question was addressed here.

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-733#post-942233

order with respect to [CH3CHO] is 1
order with respect to [CH3OH] is 1

You would need answers to part a and b to find order with respect with H+, compare any two experiments and also sub in orders with respect to [CH3CHO] and [CH3OH].

e.g
Experiment 1 and 4

View attachment 58772

Thank you so much!

 

[Salonee B]

The numerical value for Ksp is 2.00 x 10–11. Calculate [Mg2+(aq)] in a saturated
solution of Mg(OH)2. Please help, I dont understand the mark scheme

 

[Metanoia]

The numerical value for Ksp is 2.00 x 10–11. Calculate [Mg2+(aq)] in a saturated
solution of Mg(OH)2. Please help, I dont understand the mark scheme

I'm assuming that your Ksp refers to the Ksp of Mg(OH)2.

 

[Salonee B]

I'm assuming that your Ksp refers to the Ksp of Mg(OH)2.

View attachment 58790

thank you very much!! And I will see to it that the stated details are included

 

[shahzaib9291]

can somebody guide me any good acdmy for A2 karachi?

 

[nehaoscar]

How is the mechanism nucleophilic substitution?
The CH3-CH2 attaches to the NH removing HBr, and the CH2 has a positive delta... so wouldn't it be electrophilic...
Please explain why it's nucleophilic :/
Metanoia

 

[nehaoscar]

Winter 2014 - P43 - Q8-c
Part i I got the same as ms

Can someone please explain how R has 4 absorptions
And how P and Q have 5

I got S as 2 because of the CH3 and CHO groups
P = CH3 , CH2 , CHO , CH3-CO and which other groups??
Similarly which ones for Q and R??
Metanoia

 

[Youknowwhoo]

Someday I'm gonna raid this thread and learn the stuff i need from here,has anyone tried this?