<p>Say if you are trying to solve Ksp for A2B3
would the rule be Ksp= (2[A])^2(3*)^3 or simply [A]^2*^3?</p>
<p>cuz barrons says its the first one and PR says its the second one W . T. F</p>
<p>i'm sorry i've never taken AP chem and this stuff is totally new to me lol :) ... i'm "self study" AP in 1 day</p>
<p>ok, so lets assume A2B3 breaks into 2A + 3B</p>
<p>Ksp would be (assuming theyre both gases) [A]^2 x **^3, assuming u did the problem right.</p>
<p>sometimes, you NEED to multiply by 2 or 3; check how they did the problem, and you'll figure out why.</p>
<p>If you are using A2B3 in a problem you would use the second one. So if you were looking for "s," use:
Ksp=(2[A])^2(3**)^3 or Ksp=108s^5; s= (Ksp/108)^(1/5)</p>
<p>I figured out what you're confused about.</p>
<p>Let's assume we had 7.5 x 10^-4 molarity for Ca(OH)2.
So molarity of OH- is (7.5 x 10^-4) x 2 (since you have 2 of OH-). And THEN you plug this in into the equation A^2B^3. You're just plugging the first part into the equation. There you go; its the same method.</p>
<p>thank you that finally makes total sense :)</p>
<p>yeah thats right, mashimaroban</p>