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Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread

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Original post by PlayerBB
The melting temperature is 136 for TiCl3

How shall I know the structure of TiO2 and TiCl3 in order to answer this question ?


Nothing is mentioned regarding it?
Original post by PlayerBB
The melting temperature is 136 for TiCl3

How shall I know the structure of TiO2 and TiCl3 in order to answer this question ?


Do you remember any of that GCSE stuff on giant lattice and simple covalent structures?
Original post by sabahshahed294
Nothing is mentioned regarding it?


No :frown:

I don't know if that counts for something but they said at the beginning of section C that TiO2 is a non-toxic solid at room temperatire
(edited 7 years ago)
Original post by Ayman!
Do you remember any of that GCSE stuff on giant lattice and simple covalent structures?


Yeah barely!! (ugh I have to revise it then)

But how did you know Ayman that they were related to a giant lattice structure and simple covalent, the first thing that came up into my mind was that TiCl3 might be a trigonal planar
Original post by PlayerBB
No :frown:


I hate Unit 5 for this reason. The questions are sort of a nightmare :s-smilie:
I think it's to do with electron configuration of Ti. Like you sort of link it with TiO2 and TiCl3. (In TiO2, Ti has +4 oxidation state and in TiCl3, it's +3). Not sure though. Taking a guess xD :bricks:
Original post by sabahshahed294
I hate Unit 5 for this reason. The questions are sort of a nightmare :s-smilie:
I think it's to do with electron configuration of Ti. Like you sort of link it with TiO2 and TiCl3. (In TiO2, Ti has +4 oxidation state and in TiCl3, it's +3). Not sure though. Taking a guess xD :bricks:


Yeah, they are :frown:

Yeah I think that's good point (I will try to consider the electron configuration and we'll see how it goes :h:)
Original post by PlayerBB
Yeah barely!! (ugh I have to revise it then)

But how did you know Ayman that they were related to a giant lattice structure and simple covalent, the first thing that came up into my mind was that TiCl3 might be a trigonal planar

You don't need to revise it haha, it's just the first thing that came to mind when I spotted such a huge difference.


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Original post by Ayman!
You don't need to revise it haha, it's just the first thing that came to mind when I spotted such a huge difference.


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haha, well that's a relief and yeah then when I see such a huge difference then I should immediately consider these two structures!!

And btw, I just saw your post above, and just be strong and try not to have a mental break down, it won't do you any good! Plus, you're so smart and just solve the rest of the IAL papers and I think you'll see a big difference (although I haven't started solving the IAL paper myself haha)
Hello! One quick question. Are we supposed to know how to name complex ions? (cupprate...) Thanks
Original post by PlayerBB
haha, well that's a relief and yeah then when I see such a huge difference then I should immediately consider these two structures!!

And btw, I just saw your post above, and just be strong and try not to have a mental break down, it won't do you any good! Plus, you're so smart and just solve the rest of the IAL papers and I think you'll see a big difference (although I haven't started solving the IAL paper myself haha)

Remember the difference between diamond and graphite? It's something like that. The mark scheme was surprisingly lenient with this one. I think I got this section C in my first mock back in December and I just left the entire 4 marks empty lol. :tongue:

Haha I was only (half) joking, but thank you :hugs: I'm just worried that if I get a C on this paper I'll get a B overall and I can't let that happen. Organic chemistry and transition metals aren't topics that come naturally to me since I'm not naturally a chemist/biologist :tongue: No doubt that I'm actually enjoying things though!

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Original post by PlayerBB
The melting temperature is 136 for TiCl3

How shall I know the structure of TiO2 and TiCl3 in order to answer this question ?


Consider the shape of each of them and how that is going to effect what sort of structure they will be as a whole
Original post by sabahshahed294
I hate Unit 5 for this reason. The questions are sort of a nightmare :s-smilie:
I think it's to do with electron configuration of Ti. Like you sort of link it with TiO2 and TiCl3. (In TiO2, Ti has +4 oxidation state and in TiCl3, it's +3). Not sure though. Taking a guess xD :bricks:


Original post by PlayerBB
Yeah, they are :frown:

Yeah I think that's good point (I will try to consider the electron configuration and we'll see how it goes :h:)


Original post by Ayman!
You don't need to revise it haha, it's just the first thing that came to mind when I spotted such a huge difference.


Sent from my SM-G920I using Tapatalk


Firstly the question is actually about TiCl4 not TiCl3. Now if we look at the structure for each of them in turn:

1. TiO2 is going to be linear, so there will be a central titanium ion with a +4 charge and an oxygen on either side of it with a -2 charge. Since it's linear, if you looked at another TiO2 the negatively charged oxygens will be electrostatically attracted to the positively charged Ti on another 'unit' and vice versa, meaning you will get an ionic lattice.

2. TiCl4 will be tetrahedral, so we will have a central Ti 4+ with 4 cl- around it. In this situation, it is not really possible for us to get any real amount of electrostatic attraction. if we put 2 TiCl4 near each other, then the Cl - would be attracted to the positive titanium, HOWEVER the positive titanium is itself surrounded by 4 negatively charged chlorines which essentially get in the way (as they repel the negatively charged cl) and prevent any ionic bonds, so instead you just have a molecular structure
Original post by samb1234
Firstly the question is actually about TiCl4 not TiCl3. Now if we look at the structure for each of them in turn:

1. TiO2 is going to be linear, so there will be a central titanium ion with a +4 charge and an oxygen on either side of it with a -2 charge. Since it's linear, if you looked at another TiO2 the negatively charged oxygens will be electrostatically attracted to the positively charged Ti on another 'unit' and vice versa, meaning you will get an ionic lattice.

2. TiCl4 will be tetrahedral, so we will have a central Ti 4+ with 4 cl- around it. In this situation, it is not really possible for us to get any real amount of electrostatic attraction. if we put 2 TiCl4 near each other, then the Cl - would be attracted to the positive titanium, HOWEVER the positive titanium is itself surrounded by 4 negatively charged chlorines which essentially get in the way (as they repel the negatively charged cl) and prevent any ionic bonds, so instead you just have a molecular structure


Alright! :smile: But for point 2, you mentioned that TiCl4 has a molecular structure. How does the repulsion help in doing so? :s-smilie: (kind of confused)
Original post by sabahshahed294
Alright! :smile: But for point 2, you mentioned that TiCl4 has a molecular structure. How does the repulsion help in doing so? :s-smilie: (kind of confused)


That's why you cant have an ionic structure, it doesn't 'help' as such
Original post by samb1234
That's why you cant have an ionic structure, it doesn't 'help' as such


I think I got it now. Thank you! :smile:
Hey does anybody know why benzene reactions must be undergone in anhydrous conditions however phenolic reactions can be carried out in aqueous conditions. I gather it may be due to the reactivity difference but I can't quite figure out how the reactivity would allow the compound to react in different conditions.

cheers
Original post by jwanjwan
Hey does anybody know why benzene reactions must be undergone in anhydrous conditions however phenolic reactions can be carried out in aqueous conditions. I gather it may be due to the reactivity difference but I can't quite figure out how the reactivity would allow the compound to react in different conditions.

cheers


They don't. Unless you're using something that reacts violently with water, e.g. AlCl3 which does this https://hml.cardiff.ac.uk/Play/180 (about 25s in)
Original post by samb1234
They don't. Unless you're using something that reacts violently with water, e.g. AlCl3 which does this https://hml.cardiff.ac.uk/Play/180 (about 25s in)


ah i see. due to phenol being more reactive it doesnt have the need for alcl3 the catalyst so can be carried out in aqueous conditions. thank you
do we need to know about batteries?? there's a whole HSW page on them but it's not in the specification and I don't think it has ever come up in the papers...
@samb1234 wait so does alkylation/acylation of phenol still require AlCl3 in dry ether?

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