[jnimagine]

A 10.00g sample of Ca(OH)2 (Ksp=4.7x10^-6) is added to 250.0mL of pure water.  Determine the pH of the solution after just enough HCl is added to completely dissolve the Ca(OH)2.  Assume that there is no change in the solution volume during the addition of HCl.

so...I was quite lost with this question....what's the relationship between Ksp and pH...? :S

also, here's a similar question that i didn't get...

A saturated solution of calcium hydroxide has a pH of 12.25.  What is the [Ca2+] of such a solution?  What could you add to the solution to further dissolve calcium hydroxide?

[Loyal]

You have a salt that contains OH correct?  What effect does OH have on the pH of water when it is dissolved?

[jnimagine]

You have a salt that contains OH correct?  What effect does OH have on the pH of water when it is dissolved?

so.. it raises the pH right...?
but in solving this question then.... u first need to find molar solubility x with ksp... and then what do u do...?
i'm still confused.... ^^;;

[Borek]

A 10.00g sample of Ca(OH)2 (Ksp=4.7x10^-6) is added to 250.0mL of pure water.  Determine the pH of the solution after just enough HCl is added to completely dissolve the Ca(OH)2.  Assume that there is no change in the solution volume during the addition of HCl.

This one is tricky at first sight, but easy when you look longer

"Juest enough HCl is added to completely dissolve the Ca(OH)₂" means you have a saturated solution containing known amount of Ca²⁺. Use Ksp and [Ca²⁺] to calculate [OH^-].

A saturated solution of calcium hydroxide has a pH of 12.25.  What is the [Ca2+] of such a solution?  What could you add to the solution to further dissolve calcium hydroxide?

First part is an almost direct application of Ksp. Answer to the second part is in the first question you have posted.

[jnimagine]

A 10.00g sample of Ca(OH)2 (Ksp=4.7x10^-6) is added to 250.0mL of pure water.  Determine the pH of the solution after just enough HCl is added to completely dissolve the Ca(OH)2.  Assume that there is no change in the solution volume during the addition of HCl.

This one is tricky at first sight, but easy when you look longer

"Juest enough HCl is added to completely dissolve the Ca(OH)₂" means you have a saturated solution containing known amount of Ca²⁺. Use Ksp and [Ca²⁺] to calculate [OH^-].

A saturated solution of calcium hydroxide has a pH of 12.25.  What is the [Ca2+] of such a solution?  What could you add to the solution to further dissolve calcium hydroxide?

First part is an almost direct application of Ksp. Answer to the second part is in the first question you have posted.

oh i get it so for the second problem, i basically do the same thing right? i find [OH-] from pH and then since there are two moles of OH- per mole of Ca(OH)2, divide that by 2 to get [Ca2+]?

then how is this question different from a question that gives mass of sample of Ca(OH)2 added to certain amt of water, and asks us to determine the pH of the solution once equilibrum is established...
Isn't it the same method as the one where your adding HCl to get saturated solution...??
give the Ksp, don't u basically do the same thing....? - . - but... they're supposed to be different somehow.... lol

[Borek]

To some extent all these questions are identical

The diieference here is that in the first case there is no simple dependency 2[Ca²⁺] = [OH^-].