pH and pOH
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Re: pH and pOH
dont know what the question says but I think for most questions it specifies to solve for either one or the other or both
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Re: pH and pOH
I don't know what the problem says but usually, it will tell you what to solve for in the problem. Given the reaction, you will know what you have to solve for. For instance if it NH3 + H20 -> NH4+ + OH- you would solve for Kb and pOH and if it was HCl + H20 -> Cl- + H30+.
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Re: pH and pOH
If it doesn't tell you explicitly, just go off of what's present in the equation. Which do you end up with in the products - H3O+ or OH-? If it's OH-, then pOH. If it's H3O+, then pH. And of course you can always calculate one once you have the other using the equation pH + pOH = 14.
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Re: pH and pOH
The question will ask you to solve for pH or pOH, and the problem will also give you sufficient information to be able to solve for this.
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Re: pH and pOH
Also, when your chemical reaction includes H30+, you are finding the pH, and when it includes OH-, you are finding the pOH. Make sure to use the equation pH+pOH=14 if you are trying to convert between the two.
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Re: pH and pOH
Typically if you are given a base, you solve for pOH, but if you are asked to find the pH, then you must convert from pOH to pH by using this formula: -14.00 = pOH + pH. Or 14.00 - pOH = pH
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Re: pH and pOH
Usually the problem you are solving will tell you which one to solve for. In some occasions you may have to solve for both for the same problem.
Re: pH and pOH
Often times if they don't say it outright, you can infer through whether they are referring to the concentrations of acids or bases in a solution.
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Re: pH and pOH
If it doesn’t say specifically look at the products as OH would be pOh and H3O would be pH, sometimes it will tell you specifically
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Re: pH and pOH
It is always best to go with what is given, if OH is formed, then solve for pOH and then 14-pOH to find pH. If H+ is a product of the disassociation, then solve for pH and then use 14-pH if they are asking for pOH?
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Re: pH and pOH
The problem should specify, but if not it is usually safe to assume you should calculate for what is given, ie if the reaction forms H+ ions you should solve for pH and if OH- ions are formed solve for pOH.
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