Jump to content
Sign in to follow this  
Aka

precipitate

Recommended Posts

How can you predict weather or not a precipitate will form in a chemical reaction?

can some one pleas help me with this i have no idea what the answer is :confused:

Share this post


Link to post
Share on other sites
How can you predict weather or not a precipitate will form in a chemical reaction?

can some one pleas help me with this i have no idea what the answer is :confused:

I believe you get an insoluble compound chart and check for any compounds in the solvents? I'm not sure though.

Share this post


Link to post
Share on other sites
I believe you get an insoluble compound chart and check for any compounds in the solvents? I'm not sure though.

Yup, this is correct. Some easy rules to follow are that all metal nitrates are soluble, and most metal chlorides are soluble (with the exception of PbCl2 coming to mind most readily). Other rules like these exist, and can be found on Goggle :)

Share this post


Link to post
Share on other sites

If you know the concentration of the ions in the solution, and the Ksp of the compounds in question that may form, you can predict if a precipitate will form.

Share this post


Link to post
Share on other sites

another tip is that Group 2 elements become increasingly less soluble as you down the group.

Share this post


Link to post
Share on other sites

maybe i could ask for some advice here.

 

i would like to crystalise a complex of Mg5-IP6 (IP=inositol polyphosphate).

i have made the complex, it readily forms a precipitate and is very insoluble - ie soluble at concentrations of 10-100uM; this is more insoluble than all proteins i have worked on.

i can resolubilise the Mg5-IP6 precipitate in NH4 acetate, or other salts, but NH4 seems best. i have tried to evaporate the NH4 acetate at 40C in a vacuum with the hope that crystals of the Mg5-IP6 might form, but no, i still get a precipitate.

 

any suggestions to how i could get crystals would be welcome.

Share this post


Link to post
Share on other sites

Try to determine whether this compound dissolves in slightly acidic liquids. I do not know this particular compound, but the polyphosphate part makes me think that it is more soluble in slightly acidic liquids. Try an acid, which forms highly soluble salts with Mg. I would start trying with very dilute HCl, or dilute NaOAc with some acetic acid in it (buffer).

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.