ways to remember solubility rules?

[scarfscarfscarf]

i'm sort of at a lost as to how to memorize all of them? are they even that important? i rarely see them on practice tests

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[Compass]

Know em or you don't. They help, but I don't recall being ASKED which is going to precipitate. However, it should be blatantly obvious.

 

[thebillsfan]

i had a question one time that gave a table with various salts and it showed CaF being insoluble. This goes against the solubility rules I know, but I could imagine it being true if you have a diff threshold for solubility. Is this type of thing--where the solubility data goes against the rules you know--something anyone has experienced?

 

[LostInStudy]

Most books I've seen don't list F as being soluble. If you look at your textbook or review book closely then it should not mention F as being soluble. The solubility rules do say halides but F is usually not included. I did learn in my G. Chem class though that F is not soluble as the rest of the halides are. If you think about it, this is true because HF is the only weak halide acid.

To the OP: Just spend a few minutes with it and do practice questions. It's just all about how many times you see them. The more times you see them the more you remember.


Hope this helps,

-LIS

 

[thebillsfan]

Most books I've seen don't list F as being soluble. If you look at your textbook or review book closely then it should not mention F as being soluble. The solubility rules do say halides but F is usually not included. I did learn in my G. Chem class though that F is not soluble as the rest of the halides are. If you think about it, this is true because HF is the only weak halide acid.

To the OP: Just spend a few minutes with it and do practice questions. It's just all about how many times you see them. The more times you see them the more you remember.


Hope this helps,

-LIS

hm yeah youre right that does make sense if you think about it. my book did not list it as an exception. fortunately, it did not hurt me because the answer was obvious any. thanks a lot, lis.

 

[LostInStudy]

No book I have ever seen has explicitly stated it as an exception. I'm not sure why. If you look at EK Chemistry book, they list all the halides except F but don't really mention it as an exception. It's a very easy thing to overlook if you're not looking very carefully.

-LIS

 

[stargirl0912]

Solubility Rules Poem​

If you know your solubility,
Predicting reactions will come easily.

Chloride, Bromide, Iodide
Will always dissolve - that ain't no lie.
Except when paired with silver or lead,
And mercury too is one to dread.

Salts of ammonium and Group one,
When put into water will be undone.
Many others share this fate,
Such as Chlorates, Nitrates and Acetates

Sulfates too, most of the time,
But with Strontium or Barium will not be prime.
Nor will lead and mercury,
Aqueous Ions be.
And know you know your solubility.

 

[IndianVercetti]

Found this excellent post on here months ago, and this is the method I use to memorize them:

Here is SilvrGrey330's extremely clever mnemonic to remember salt solubility rules.

C A S H n Gia

Read it as "Cashin' Gia"...how to remember that? well the story is...im a pimp...and gia is my hoe, and i need to get my cash from her. hence...Cashing from gia.

C is chlorates, A is acetates, S is sulfates, H is halogens, n is Nitrates, and Gia is Group I A metals. ---> THESE ARE ALL SOLUBLE, XCEPT

for S: Ca, Ba, Sr.....just remember the tv network CBS
for H: Ca, Ba, Sr + Happy...whats happy? Hb Ag Pb ...mercury, silvr and lead...add a py to the end and all the first letters spell HAPPY

and if its not part of CASHnGIA...its insoluble.

It sounds really stupid, I know. But if you diagram this out in a systematic way, you can VERY quickly recall these, by quickly drawing out your trick.

Key is the memorize the diagram you draw, and write it out every time you practice, so that you'll memorize your diagram.

 

[Quaero]

These mnemonics are amazing

But... doesn't it come down to hard-soft acid-base interactions?
Look at the size/charge of the metal/nonmetal and you might see a trend going. The major reason that something is insoluble in a solvent is because the interaction between the solute molecules is stronger than the solvent's to these solutes.

 

[Abby_Normal]

Have you done any qualitative analysis? If so, review your old labs. For me, being able to remember concrete examples and processes (when I mixed X and Y a white ppt formed...) helped. It gives you a visual reference.

 

[RiPSTONE]

Just saw CASHNGIA... Trying to learn it!

 

[Tradewinds]

Just saw CASHNGIA... Trying to learn it!

Thanks for the bump!

 

[MCATQUESTIONS]

Found this excellent post on here months ago, and this is the method I use to memorize them:



It sounds really stupid, I know. But if you diagram this out in a systematic way, you can VERY quickly recall these, by quickly drawing out your trick.

Key is the memorize the diagram you draw, and write it out every time you practice, so that you'll memorize your diagram.

This is great, except it's missing some!
All ammonium salts (salts of NH4+) are soluble.
Sulfate has Pb, and Hg2 for exceptions too.