pKa vs. pH

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Lumbini Chandrasekera 1B
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Joined: Fri Sep 28, 2018 12:18 am

pKa vs. pH

Postby Lumbini Chandrasekera 1B » Thu Jan 24, 2019 11:17 am

Why isn't pKa the same as pH?

katherinemurk 2B
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Re: pKa vs. pH

Postby katherinemurk 2B » Thu Jan 24, 2019 11:21 am

pKa is a the -log of the acid dissociation constant, it is a measure of acid strength. pH is a measure of the concentration of H+ ions.

Karan Thaker 2L
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Joined: Fri Sep 28, 2018 12:26 am

Re: pKa vs. pH

Postby Karan Thaker 2L » Thu Jan 24, 2019 1:36 pm

They're both logarithmic expression of completely different things. pKa is a logarithmic expression of Ka values while pH is a logarithmic expression of hydrogen ion concentration.

Kyither Min 2K
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Joined: Wed Oct 03, 2018 12:15 am

Re: pKa vs. pH

Postby Kyither Min 2K » Thu Jan 24, 2019 5:52 pm

pKa stands for -log of Ka and pH stands for -log of Hydronium ions. Consider the p as a function rather than a symbol. All the p does is mathematically change the value, similar to a negative sign or derivative. Ka is the dissociation of an acid or the equilibrium constant for the acid whereas H is just the concentration of H3O+. The two measure different things.

Anand Narayan 1G
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Re: pKa vs. pH

Postby Anand Narayan 1G » Sun Jan 27, 2019 10:44 pm

This is because pKa is a the -log of Ka, the acid dissociation constant, it is a measure of acid strength. pH, on the other hand is a measure of the concentration of H+ ions.

405021651
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Joined: Tue Nov 14, 2017 3:03 am

Re: pKa vs. pH

Postby 405021651 » Sun Jan 27, 2019 11:14 pm

The pKa is the -log(Ka)

505211599
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Joined: Fri Sep 28, 2018 12:28 am

Re: pKa vs. pH

Postby 505211599 » Mon Jan 28, 2019 12:39 am

The pKa is the -log(Ka) and pH is -log(H+)

abbydouglas1K
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Re: pKa vs. pH

Postby abbydouglas1K » Wed Jan 30, 2019 4:21 pm

pKa and pH measure different quantities. pKa measurers acid strength and pH measures H+ concentration, which are similar but Ka is used to find pKa as opposed to a molar cpncenztrartion of H+ ions in a solution.

JacobHershenhouse3G
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Joined: Thu Jan 10, 2019 12:17 am

Re: pKa vs. pH

Postby JacobHershenhouse3G » Wed Jan 30, 2019 6:34 pm

Don't let yourself be confused by similar notation because they mean dramatically different things. p just means -log, so in this case you are taking the negative log of a constant and of a concentration, therefore it is evident that the interpretation of these numbers mean different things. Both values gives you insight on how strong or weak an acid or base. Yet, taking the pka of an acid base reaction gives you perspective in relation to pKw=1e-14 and pH does so on a scale of 0 to 14.

Zubair Ahmed 1L
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Joined: Fri Sep 28, 2018 12:16 am

Re: pKa vs. pH

Postby Zubair Ahmed 1L » Wed Jan 30, 2019 6:53 pm

The pKa and the pH represent two different things. The pKa is the -log(Ka) and can be used to determine the strength of an acid. On the other hand, the pH is the -log(H+) concentration.

Nina Do 4L
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Joined: Fri Sep 28, 2018 12:27 am

Re: pKa vs. pH

Postby Nina Do 4L » Wed Jan 30, 2019 7:42 pm

pKa is the -log of the Ka value and Ka*kB=1x10^-4 so you can find out the value of Ka/pka if you're given the value of Kb.

pH is the -log of H+ or H3O+.

The 'p' is -log-ing different values, therefore they are different. Hope this helps.

Ricardo Martin 1J
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Re: pKa vs. pH

Postby Ricardo Martin 1J » Wed Feb 06, 2019 9:28 am

pH is the concentration f hydrogen ions in the solution.

Ashley P 4I
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Joined: Wed Nov 15, 2017 3:04 am

Re: pKa vs. pH

Postby Ashley P 4I » Fri Mar 15, 2019 9:49 am

pKa= -log of Ka
pH stand= -log of Hydronium ions.

Nghi Nguyen 2L
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Joined: Fri Sep 28, 2018 12:18 am

Re: pKa vs. pH

Postby Nghi Nguyen 2L » Fri Mar 15, 2019 9:38 pm

pKa = -log(Ka)
pH = -log(H+)

Roberto Gonzalez 1L
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Re: pKa vs. pH

Postby Roberto Gonzalez 1L » Sun Mar 17, 2019 4:52 pm

pH can be solved for by taking the -log of the concentration of hydronium ions, and therefore quantitatively describes the acidity or basicity of a solution. pKa is found taking the -log of the ionization constant of an acid, and can therefore be used to understand the strength of an acid.

Anita Wong 1H
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Re: pKa vs. pH

Postby Anita Wong 1H » Sun Mar 17, 2019 5:30 pm

pka is in reference to ka whereas ph is in reference to H+


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