Precipitate from Common Ions
Download
1 / 4

Ca + - PowerPoint PPT Presentation


  • 137 Views
  • Uploaded on

Precipitate from Common Ions. Ksp = ] [ Ca + ] + [ OH¯ ]. Ca(OH) 2  Ca + + OH¯. A saturated solution starts out with the solid salt Ca(OH) 2 at equilibrium with a specific concentration of dissolved ions produced from that salt .

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Ca +' - armani


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Precipitate from Common Ions

Ksp = ][Ca+] + [OH¯]

Ca(OH)2Ca+ + OH¯

A saturated solution starts out with the solid salt Ca(OH)2 at equilibrium with a specific concentration of dissolved ions produced from that salt.

This is the normal solubility or concentration, in Molarity, of the dissociated Ca(OH)2.

The Kspis the constant for the measure of equilibrium for solubility.

Ca+

Ca+

OH¯

OH¯

OH¯

OH¯

Ca+

OH¯

OH¯

Ca+

Ca+

OH¯

OH¯

OH¯

OH¯

Ca(OH)2

Ca(OH)2


Precipitate from Common Ions

5.02 x 10-6 = [Ca+] + [OH¯]

Ca(OH)2Ca+ + OH¯

34.0 = [Na+] + [OH¯]

NaOHNa+ + OH¯

However, if there are ions from another source, in this case NaOH, that are dissociated according to a higher Ksp, then

since the Ksp of the Ca(OH)2 is lower, some of the OH- ions have to join back with some Ca+ ions to turn back into solid Ca(OH)2 so they are not counted in the Ksp expression

This is Le Chatelier’s Principle at work.

Note: this is where the term “common ions” comes from – the NaOH has the OH- ion in common with the Ca(OH)2

Ca+

Ca+

OH¯

OH-

OH-

OH¯

Ca+

OH¯

OH¯

OH¯

OH¯

Na+

Na+

Ca+

Ca+

OH¯

OH¯

OH¯

OH¯

Ca(OH)2

Ca(OH)2


Precipitate from Common Ions

Ksp = ][Ca+] + [OH¯]

Ca(OH)2Ca+ + OH¯

34.0 = [Na+] + [OH¯]

NaOHNa+ + OH¯

Some of the Ca2+ ions reassociate with the OH- ions and turn to solid (or precipitate out).

Ca+

Ca(OH)2

OH¯

OH¯

Ca+

OH¯

OH¯

OH¯

OH¯

Na+

Na+

Ca+

Ca(OH)2

OH¯

OH¯

Ca(OH)2

Ca(OH)2


Precipitate from Common Ions

Ksp = ][Ca+] + [OH¯]

Ca(OH)2Ca+ + OH¯

34.0 = [Na+] + [OH¯]

NaOHNa+ + OH¯

The solution is again at equilibrium even though the concentrations of Ca+ions and OH-ions from the Ca(OH)2 salt are lower than previous.

Ca+

OH¯

OH¯

Ca+

OH¯

OH¯

OH¯

OH¯

Na+

Na+

Ca+

OH¯

OH¯

Ca(OH)2

Ca(OH)2

Ca(OH)2

Ca(OH)2


ad