pH formula?

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Saleha_Mian_3E
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pH formula?

Postby Saleha_Mian_3E » Mon Dec 03, 2018 10:14 pm

What is the pH formula? and do we need to know how it was derived?

Sierra Cheslick 2B
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Re: pH formula?

Postby Sierra Cheslick 2B » Mon Dec 03, 2018 10:24 pm

The pH formula is -log[H+]. I believe we would need to know how to derive it.

305127455
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Re: pH formula?

Postby 305127455 » Tue Dec 04, 2018 8:29 pm

I don't think we need to know how to derive it since pH is just an invented representation of proton concentration. For acid it's (-log[H+]), for base it's 14 - (-log[OH-])

Jonathan Cheng 3C
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Re: pH formula?

Postby Jonathan Cheng 3C » Thu Dec 06, 2018 5:08 pm

pH = - log[H+] while pOH is either 14 - pH or -log[OH-]. We do not need to know how these formulas were derived.

Henri_de_Guzman_3L
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Re: pH formula?

Postby Henri_de_Guzman_3L » Thu Dec 06, 2018 8:01 pm

We don't need to know how they're derived although reading through the textbook I feel it is helpful in understanding how they work.

Krista Mercado 1B
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Re: pH formula?

Postby Krista Mercado 1B » Sat Dec 08, 2018 5:11 pm

The pH formula is pH = -log[H+]. I don't think we need to know how it is derived.

Lisa Werner 2F
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Re: pH formula?

Postby Lisa Werner 2F » Sat Dec 08, 2018 5:25 pm

I think you also need to know that pH + pOH = 14.

Karina Koo 2H
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Re: pH formula?

Postby Karina Koo 2H » Sun Dec 09, 2018 10:01 am

@305127455 wait shouldnt pOH be 14-(-log[H+]) ?

NRodgers_1C
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Re: pH formula?

Postby NRodgers_1C » Sat Nov 30, 2019 7:16 pm

Don't forget that because pH= -log[H3O+]= -log(1.0x10-7) = -(-7)=7 for a change in 1 pH unit, the [H3O+] changes by a factor of 10.

gferg21
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Re: pH formula?

Postby gferg21 » Sat Nov 30, 2019 7:42 pm

The acid and base concentrations of the formula add up to 14, so there may be a pH of 8, which means there is a pOH of of 6

MBouwman_4A
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Re: pH formula?

Postby MBouwman_4A » Mon Dec 02, 2019 8:35 am

The formula for pH is -log[H+] and pOH is -log[OH-]. I don't think we need to know the derivation, but it is helpful to know that pH + pOH = 14

Callum Guo 1H
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Re: pH formula?

Postby Callum Guo 1H » Mon Dec 02, 2019 8:47 am

pH=-log[h+]

preyasikumar_2L
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Re: pH formula?

Postby preyasikumar_2L » Mon Dec 02, 2019 8:54 am

You just need to know how to calculate pH and pOH from the [H+] and [OH-] given, and vice versa. pH = -log([H+]) and pOH = -log([OH-]) = 14 - pH

Mitchell Koss 4G
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Re: pH formula?

Postby Mitchell Koss 4G » Mon Dec 02, 2019 6:32 pm

No you do not need to understand how logarithms are derived

Juana Abana 1G
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Re: pH formula?

Postby Juana Abana 1G » Mon Dec 02, 2019 7:27 pm

so is it fine to just know the pH formula?

Claire Grover 3G
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Re: pH formula?

Postby Claire Grover 3G » Mon Dec 02, 2019 7:39 pm

The formula is -log[H+] but I'm not sure if we need to know how to derive that.

chrischyu4a
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Re: pH formula?

Postby chrischyu4a » Sat Dec 07, 2019 4:26 pm

pH=-log[H3O+]

Callum Guo 1H
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Re: pH formula?

Postby Callum Guo 1H » Sat Dec 07, 2019 9:15 pm

it's -log[h+] and i doubt we would need to derive it

AveryAgosto
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Re: pH formula?

Postby AveryAgosto » Sat Dec 07, 2019 9:17 pm

-log[H+] and I think we just need to know that pH+pOH= 14

Annie Ye
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Re: pH formula?

Postby Annie Ye » Sun Dec 08, 2019 6:19 pm

pH= -log(H+) you can also find pH from the equation 14= pOH+ pH if you were given the pOH.

Natalie C 1K
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Re: pH formula?

Postby Natalie C 1K » Sun Dec 08, 2019 7:06 pm

the pH is calculated using the formula: pH= -log[H3O+]

Leyna Dang 2H
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Re: pH formula?

Postby Leyna Dang 2H » Sun Dec 08, 2019 7:53 pm

You could find pH using pH=-log[H+]. Or, if you have the pOH, you could subtract it from 14 to find the pH.

Stacey Phan 2K
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Re: pH formula?

Postby Stacey Phan 2K » Thu Dec 03, 2020 1:08 am

You can use the formula pH = - log[H+]

lwon Dis2I
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Re: pH formula?

Postby lwon Dis2I » Sat Dec 05, 2020 2:44 pm

What is the difference between pH=-log[H3O+] and pH=-log[H+]?

Sophia Spungin 2E
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Re: pH formula?

Postby Sophia Spungin 2E » Sat Dec 05, 2020 2:59 pm

Professor Lavelle mentioned that when you see 'p' in chemistry it means take the negative log. So 'pH' means to take the negative log of the species with H+, or H3O+

Jasraj Parmar 3H
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Re: pH formula?

Postby Jasraj Parmar 3H » Sat Dec 05, 2020 4:38 pm

The pH forumla is pH = - log [H3O+].

Yeprem
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Re: pH formula?

Postby Yeprem » Sun Dec 06, 2020 5:04 pm

P itself just stands for -log
When you say pH it means calculating the -log [H3O+] where the brackets show the concentration of the H3O+ ion
pOH is -log[OH-]

jasmineculilap_3F
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Re: pH formula?

Postby jasmineculilap_3F » Sun Dec 06, 2020 5:10 pm

pH = -log[H+]. I don't think we need to how it was derived.

Ava Nickman
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Re: pH formula?

Postby Ava Nickman » Sun Dec 06, 2020 5:13 pm

pH= -log[H+]
pH= 14-pOH
pH= 14 - (-log[OH-])

it depends on what you are given

305614361
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Re: pH formula?

Postby 305614361 » Sun Dec 06, 2020 5:19 pm

The pH formula is pH = -log10[H+] and [H+] = 10^-pH

Jack_Pearce_2H
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Re: pH formula?

Postby Jack_Pearce_2H » Sun Dec 06, 2020 11:13 pm

I don't think you need to know how it was derived but definitely know that ph=(-log([H+]) and that [H+]=10^(-pH)

Ethan Goode 2H
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Re: pH formula?

Postby Ethan Goode 2H » Sun Dec 06, 2020 11:14 pm

The formula is -log[H+], basically just measuring the amount of protons in a solution, determining if it is acidic or basic.

Joshua Eidam 2A
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Re: pH formula?

Postby Joshua Eidam 2A » Wed Dec 09, 2020 2:45 pm

Just to clarify, when using the concentration of OH to find the pH, you simply subtract -log[OH-] from 14 and that will equal the pH?
Last edited by Joshua Eidam 2A on Wed Dec 09, 2020 2:50 pm, edited 1 time in total.

Joshua Eidam 2A
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Re: pH formula?

Postby Joshua Eidam 2A » Wed Dec 09, 2020 2:46 pm

lwong Dis1L wrote:What is the difference between pH=-log[H3O+] and pH=-log[H+]?

They are the same thing. The H3O+ just represents the H+ bonded with an H2O but the concentration of either of them can be used to find the pH.

Joshua Eidam 2A
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Re: pH formula?

Postby Joshua Eidam 2A » Wed Dec 09, 2020 2:50 pm

Also, when trying to find the concentration of the H+ or OH- from a pH or pOH, how do you do the reverse of -log[ ]?

Nick Saeedi 1I
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Re: pH formula?

Postby Nick Saeedi 1I » Thu Dec 10, 2020 7:09 pm

The pH formula is -log[H+].

Ariel Guan 1H
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Re: pH formula?

Postby Ariel Guan 1H » Thu Dec 10, 2020 7:57 pm

pH = -log[H+]
[H+] = 10^(-pH)
pOH = -log[OH-]
[OH-] = 10^(-pOH)
14 = pH + pOH

DPatel_2L
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Re: pH formula?

Postby DPatel_2L » Fri Dec 11, 2020 8:00 pm

pH=-log[H+]

Kaili Valenzuela 2B
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Re: pH formula?

Postby Kaili Valenzuela 2B » Fri Dec 11, 2020 8:05 pm

Hi! I think this would be helpful to know
pH=14.00-pOH= -log[H+]
pOH=14.00-pH= -log[OH-]

Mingzi Yang 1E
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Re: pH formula?

Postby Mingzi Yang 1E » Fri Dec 11, 2020 11:08 pm

Ariel Guan 1G wrote:pH = -log[H+]
[H+] = 10^(-pH)
pOH = -log[OH-]
[OH-] = 10^(-pOH)
14 = pH + pOH

This is helpful! Thank you.

Lorraine Jiang 2C
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Re: pH formula?

Postby Lorraine Jiang 2C » Sat Dec 12, 2020 12:15 am

Hi! The formula to calculate pH is -log[H+]

Hope it helps!

Kayla Booker 1F
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Re: pH formula?

Postby Kayla Booker 1F » Sat Dec 12, 2020 12:38 am

pH formula is pH=-log[H+] and Im not sure if we need to know how it's derived, but another formula for pH is pH=14.00-pOH

Sophia Kalanski 1A
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Re: pH formula?

Postby Sophia Kalanski 1A » Sun Dec 13, 2020 1:11 am

pH=-log[H+]
it's also helpful to note that pH+pOH=14 and that [H+][OH-]=1*10^-14

Andy Hernandez
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Re: pH formula?

Postby Andy Hernandez » Wed Dec 16, 2020 10:15 pm

The pH formula is -log[H+]

805421690
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Re: pH formula?

Postby 805421690 » Wed Dec 16, 2020 10:17 pm

acid: (-log[H+]
base: 14 - (-log[OH-])

Nicole Bruno Dis 1B
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Re: pH formula?

Postby Nicole Bruno Dis 1B » Thu Dec 17, 2020 4:19 am

The pH formula is -log[H+], and to derive it, you should know how to determine its relation to pKa and pOH.

Sejal Parsi 3K
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Re: pH formula?

Postby Sejal Parsi 3K » Thu Dec 17, 2020 7:47 am

pH= -log[H+] and you don’t need to know how to derive it.


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