Variable oxidation states - Cobalt Chemistry

[@manicat81]

Thanks, I really liked this video. My text book doesn't go into as much depth, and even though this video is only 8 minutes, I understand that ammonias are taking the 2xH+ from the H2O ligands (acting as a base as you say) (wasn't made very clear in my AQA book) and also that there's a precipitate/solid because it now has a 0 charge so that's something I can look out for in other examples. Plus it's good to have the colour changes made clear. In short, I get your explanation much better!

[@AlleryChemistry]

You're very welcome!

[@fluffyteddyber4077]

Love the vid! Just wanted to suggest you lock down the focus and the exposure. :)

[@mightymot45]

Nice- been waiting for this one! :)

[@AlleryChemistry]

mightymot45 Good things come to those who wait as the saying goes. Glad it helps. Thanks for sharing the vid too!

[@pwincezzetz]

I can't find this on the new AQA spec, don't we just need to know the Vanadium oxidation reactions?

[@AlleryChemistry]

Cobalt has been removed from AQA but vanadium is now on as you say.

[@shockwave16081]

which variable oxidation state elements do you need to know for the current aqa a-level spec?

[@dedicatedanna]

Great video helps me with my assignment 👍👍👍👍

[@ismaeelahmed4873]

Is there a video on vanadium for the AQA new spec?

[@Lunchfanchannel]

thanks ! just have a question. why does copper hexaqua (II) ion need only 4 ammonia to form [Cu(NH3)4(H2O)2]2+ whereas cobalt haxaqua (II) ion need 6 ammonia to form [Co(NH3)6]2+ ? My question is why aren't all the water molecules in cupper complex replaced by ammonia and 2 water molecules remained? (when reacted with excess of ammonia)

[@AlleryChemistry]

Yes the 2 water molecules left over have stronger bond enthalpies than the other 4 and hence are not released in copper complexes. The full explanation is much more complex than this and goes beyond the a level spec.

[@Lunchfanchannel]

+Allery Chemistry thank you so much! Ive just finished my chem A2 exam today and I think it went well! thanks to you! your videoes really helped me a lot.

[@9clpc858]

Hi Sir, would you have time to upload another AQA CHEM5 past paper video?

[@AlleryChemistry]

+9clpc8 Hello. I will certainly try.

[@reiantaank3314]

Thanks for this. I think [Co(NH3)6]3+ is a brown solution according to AQA

[@AlleryChemistry]

+Reian Taank No problem. Yes it is actually supposed to be orange however is brown when contaminants are in the solution this is probably the reason why AQA say brown. If you check the mark schemes you may find they will accept both. Hope this helps!

[@reiantaank3314]

+A Level Chemistry by Allery Tutors Ok, thanks!

[@AlleryChemistry]

+Reian Taank No problem