Finding pH, pOH, H+ and OH-!
There are two things that tell you if an acid is strong.
1. pH scale 2. By the concentration of ions it produces. (H+) There is a mathematical relationship between the two. It is a formula: pH = -log [H+] If you want to find the pOH the formula changes to: pOH = -log [OH-] *The brackets stand for consentration. Finding pH and pOH: For example find the pH for this: (H+) = 0.1M Just plug it into the formula! But you cant do this all on your own. So, I'm going to teach you how to do this on your calculator. How to plug into calculator: (Directions apply to graphing calculators) Step 1: Press the - button on the lower right hand corner of your calculator. Step 2: Press the log button. Step 3: When this pops up on your screen~ -log( ~fill the parenthesis with the value for H+ (which in this case would be 0.1) Step 4: Close your parenthesis by clicking the parenthesis button directly above the number 9. Step 5: Click enter. This is what you should have on your calculator: -log(0.1) = 1 If these directions were not helpful, watch this video: |
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Once you've found the pH, you can now find the pOH.
Lets do some review:
There is 14 numbers on the pH scale. And pH + pOH = 14 Remember?
So in this case, if the pH = 1 the pOH must = 13
Feel like you understand everything? Take the quiz!
If not go to the next page to calculate H+ and OH-.
Lets do some review:
There is 14 numbers on the pH scale. And pH + pOH = 14 Remember?
So in this case, if the pH = 1 the pOH must = 13
Feel like you understand everything? Take the quiz!
If not go to the next page to calculate H+ and OH-.