Ca(OH)2 model? Watch

Kat the Great
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I have to make a Calcium Hydroxide model for a chemistry project in school, but I'm not sure what said model would look like. I would assume a lewis structure, but I'd need some help on how that would look; the covalent/ionic bonding differences are confusing me.:banghead:
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George0123
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So it's an ionic solid Ca^2+ OH- OH- right? The exact structure of which would be quite complicated for your level. For your interest we define the structure of a ionic solid by the unit cell which is basically a polyhedra (containing the ions of the solid) that can be repeated multiple (infinite) times to build up the total crystal structure. The unit cell is essentially a small slice of the structure.

However all of this above is about the solid in its pure form. If however the problem is to depict the structure of the AQUEOUS solid (ie added to water) then this is a different problem entirely. You may well know that most aqueous ions in water have an octahedral coordinate bond "Lewis structure" , I think we did this at A-level. Sorry for the ramble I just wanted to make sure it was clear If you want me to clarify anything ask.


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George0123
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I think at this level your teacher would probably want a "Lewis dot structure" and to understand that it is an ionic solid.


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username913907
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(Original post by Kat the Great)
I have to make a Calcium Hydroxide model for a chemistry project in school, but I'm not sure what said model would look like. I would assume a lewis structure, but I'd need some help on how that would look; the covalent/ionic bonding differences are confusing me.:banghead:

(Original post by George0123)
So it's an ionic solid Ca^2+ OH- OH- right? The exact structure of which would be quite complicated for your level. For your interest we define the structure of a ionic solid by the unit cell which is basically a polyhedra (containing the ions of the solid) that can be repeated multiple (infinite) times to build up the total crystal structure. The unit cell is essentially a small slice of the structure.

However all of this above is about the solid in its pure form. If however the problem is to depict the structure of the AQUEOUS solid (ie added to water) then this is a different problem entirely. You may well know that most aqueous ions in water have an octahedral coordinate bond "Lewis structure" , I think we did this at A-level. Sorry for the ramble I just wanted to make sure it was clear If you want me to clarify anything ask.


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Look at the wikipedia page for CaOH2

It adopts a cadmium iodide like structure.
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Borek
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username913907
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(Original post by Borek)
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Borek
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(Original post by JMaydom)
Look at the wikipedia page for CaOH2
Wikipedia has no page on calcium hydrate
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username913907
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(Original post by Borek)
Wikipedia has no page on calcium hydrate
I know you're a fan of this :P

http://lmgtfy.com/?q=calcium+hydroxide
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Borek
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No no, CaOH2 is not the calcium hydroxide. It is a combination of calcium and oxide dihydride, AKA dihydrogen monoxide.
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charco
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(Original post by Borek)
No no, CaOH2 is not the calcium hydroxide. It is a combination of calcium and oxide dihydride, AKA dihydrogen monoxide.
Now it's definitely time to lay off the psychotropic turkey stuffing ...
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username913907
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(Original post by Borek)
No no, CaOH2 is not the calcium hydroxide. It is a combination of calcium and oxide dihydride, AKA dihydrogen monoxide.

(Original post by charco)
Now it's definitely time to lay off the psychotropic turkey stuffing ...
Yeah, seriously. WTF?

Do i sense a drunken foray into the world of trolling?

Or was this part of a master plan.... win a TSR award and then start trolling?
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Borek
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Well, I thought you missed parentheses. But as there are two of you not seeing that, you are probably right, and CaOH2 is a correct formula of calcium hydroxide.

So many things to unlearn... :rolleyes:
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username913907
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(Original post by Borek)
Well, I thought you missed parentheses. But as there are two of you not seeing that, you are probably right, and CaOH2 is a correct formula of calcium hydroxide.

So many things to unlearn... :rolleyes:
OR, it's an assumption based upon assumed knowledge of reasonable chemistry....... sooooo pedantic :unimpressed:
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gingerbreadman85
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(Original post by JMaydom)
OR, it's an assumption based upon assumed knowledge of reasonable chemistry....... sooooo pedantic :unimpressed:
Say that to your chemistry teacher next time they take marks off you for a symbol equation without brackets properly used......

If you're doing GCSE or A-level Chemistry, get used to having to be pedantic about chemical or displayed formula. Don't even get me STARTED on organic mechanisms......
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username913907
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(Original post by gingerbreadman85)
Say that to your chemistry teacher next time they take marks off you for a symbol equation without brackets properly used......

If you're doing GCSE or A-level Chemistry, get used to having to be pedantic about chemical or displayed formula. Don't even get me STARTED on organic mechanisms......
Umm, i'm in 4th year at uni..... Yeah and the organic mechanisms. You can tell tutors to get stuffed on being pedantic about them as for most of the ones they tend to pick up on have many possible routes which are viable. They can't actually study these mechanisms to the level of detail to dismiss the many closely related routes to the products.

And yes i did say that sort of thing to my teach back in the day
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gingerbreadman85
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(Original post by JMaydom)
Umm, i'm in 4th year at uni..... Yeah and the organic mechanisms. You can tell tutors to get stuffed on being pedantic about them as for most of the ones they tend to pick up on have many possible routes which are viable. They can't actually study these mechanisms to the level of detail to dismiss the many closely related routes to the products.

And yes i did say that sort of thing to my teach back in the day
True, however when your lecturer writes the answers to their question in your finals paper, it's hard to argue with them.

As for pedantic when it comes to A-level mechanisms, I'm thinking more missing lone pairs/charges or arrows not going quite to the right places. Stuff you'll have sorted out ages ago!
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username913907
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(Original post by gingerbreadman85)
True, however when your lecturer writes the answers to their question in your finals paper, it's hard to argue with them.

As for pedantic when it comes to A-level mechanisms, I'm thinking more missing lone pairs/charges or arrows not going quite to the right places. Stuff you'll have sorted out ages ago!
Wow, sorry but this is so patronising.
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gingerbreadman85
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(Original post by JMaydom)
Wow, sorry but this is so patronising.
I was offering A-level advice on a thread tagged "A-level". The points where the mark scheme is pedantic that I highlighted are very common mistakes that I have seen with A-level students, which I teach a large number of. Given that you are not an A-level student, I qualified the advice to make it clear that I know that you are unlikely to need it, however you are not the thread originator, nor the only person that reads it.

Unless you mean the "lecturer writing the paper" part, in which case I'm not sure what problem you have with a statement that is factually true?

Either way I apologise if I appeared patronising, that was not the aim.
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