A good tip that Kaplan teaches in their books is that when you take -log[x*10^-4] you can solve by doing 4 - 0.x to get the pH. Using your example in the video, you'd do -log[4*10^-4] = 4 - 0.4 = 3.6 which is a very close approximation.
For the last example, how would you identify that the M given is for an acid and not a base? When do you know when you need to find Ka instead of Kb? Also what are the problems where u need to account for 2 H+ or 2 OH-? Thank you!
I'm sorry, but I don't offer tutoring through RUclips comments. For help with questions like this and more, I recommend joining the MCAT Study Hall. For more details visit join.mcatstudyhall.com/ or contact me through my website leah4sci.com/contact/
![Noob To Max With DRAGON REWORK In Blox Fruits [FULL MOVIE]](http://i.ytimg.com/vi/LnBMOinoOvA/mqdefault.jpg)
A good tip that Kaplan teaches in their books is that when you take -log[x*10^-4] you can solve by doing 4 - 0.x to get the pH. Using your example in the video, you'd do -log[4*10^-4] = 4 - 0.4 = 3.6 which is a very close approximation.
Thanks for the tip!
thank you so much our teacher Leah your video was so interested
You are very welcome!
For the last example, how would you identify that the M given is for an acid and not a base? When do you know when you need to find Ka instead of Kb? Also what are the problems where u need to account for 2 H+ or 2 OH-? Thank you!
I'm sorry, but I don't offer tutoring through RUclips comments. For help with questions like this and more, I recommend joining the MCAT Study Hall. For more details visit join.mcatstudyhall.com/ or contact me through my website leah4sci.com/contact/
For both of the examples you could use the approach of converting Kb to Ka and solving for pH correct? Thanks!
No, not for both examples. If given a base, such as NH3, we use the Kb expression because NH3 reacts with water as a base, not as an acid.
So is it always going to be x^2 / Mi ?
In this context, yes, assuming the rest is negligible
PKa+PKb = 14 seems easier to get a rough answer?
Yes if you have or can calculate those values.