## pH formula?

Saleha_Mian_3E
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Joined: Fri Sep 28, 2018 12:25 am

### pH formula?

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

Sierra Cheslick 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:27 am

### Re: pH formula?

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

305127455
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Joined: Fri Sep 28, 2018 12:16 am

### Re: pH formula?

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?

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
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### Re: pH formula?

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.

Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: pH formula?

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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Joined: Fri Sep 28, 2018 12:17 am

### Re: pH formula?

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

Karina Koo 2H
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Joined: Fri Sep 28, 2018 12:24 am

### Re: pH formula?

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

NRodgers_1C
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Joined: Thu Jul 25, 2019 12:15 am

### Re: pH formula?

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
Posts: 51
Joined: Sat Aug 17, 2019 12:17 am

### Re: pH formula?

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
Posts: 40
Joined: Wed Sep 18, 2019 12:21 am

### Re: pH formula?

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?

pH=-log[h+]

preyasikumar_2L
Posts: 101
Joined: Fri Aug 09, 2019 12:17 am

### Re: pH formula?

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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Joined: Sat Jul 20, 2019 12:17 am

### Re: pH formula?

No you do not need to understand how logarithms are derived

Juana Abana 1G
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Joined: Wed Sep 18, 2019 12:15 am

### Re: pH formula?

so is it fine to just know the pH formula?

Claire Grover 3G
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Joined: Wed Sep 18, 2019 12:18 am

### Re: pH formula?

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

chrischyu4a
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Joined: Thu Jul 25, 2019 12:16 am

### Re: pH formula?

pH=-log[H3O+]

Callum Guo 1H
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### Re: pH formula?

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

AveryAgosto
Posts: 76
Joined: Wed Sep 18, 2019 12:16 am

### Re: pH formula?

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

Annie Ye
Posts: 106
Joined: Wed Sep 18, 2019 12:22 am

### Re: pH formula?

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?

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

Leyna Dang 2H
Posts: 104
Joined: Thu Jul 25, 2019 12:17 am

### Re: pH formula?

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?

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

lwon Dis2I
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Joined: Wed Sep 30, 2020 9:37 pm

### Re: pH formula?

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

Sophia Spungin 2E
Posts: 60
Joined: Wed Sep 30, 2020 9:41 pm

### Re: pH formula?

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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Joined: Wed Sep 30, 2020 9:44 pm

### Re: pH formula?

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

Yeprem
Posts: 54
Joined: Wed Sep 30, 2020 9:40 pm

### Re: pH formula?

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
Posts: 60
Joined: Wed Sep 30, 2020 9:40 pm

### Re: pH formula?

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

Ava Nickman
Posts: 60
Joined: Wed Sep 30, 2020 9:54 pm

### Re: pH formula?

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

it depends on what you are given

305614361
Posts: 52
Joined: Wed Sep 30, 2020 9:42 pm

### Re: pH formula?

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

Jack_Pearce_2H
Posts: 61
Joined: Wed Sep 30, 2020 9:48 pm

### Re: pH formula?

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
Posts: 87
Joined: Wed Sep 30, 2020 9:51 pm

### Re: pH formula?

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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Joined: Wed Sep 30, 2020 9:58 pm

### Re: pH formula?

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
Posts: 41
Joined: Wed Sep 30, 2020 9:58 pm

### Re: pH formula?

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
Posts: 41
Joined: Wed Sep 30, 2020 9:58 pm

### Re: pH formula?

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
Posts: 71
Joined: Wed Sep 30, 2020 9:39 pm

### Re: pH formula?

The pH formula is -log[H+].

Ariel Guan 1H
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Joined: Wed Sep 30, 2020 9:36 pm
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### Re: pH formula?

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

DPatel_2L
Posts: 50
Joined: Wed Sep 30, 2020 9:41 pm

### Re: pH formula?

pH=-log[H+]

Kaili Valenzuela 2B
Posts: 57
Joined: Wed Sep 30, 2020 9:55 pm

### Re: pH formula?

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

Mingzi Yang 1E
Posts: 60
Joined: Wed Sep 30, 2020 9:53 pm

### Re: pH formula?

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

Lorraine Jiang 2C
Posts: 67
Joined: Wed Sep 30, 2020 9:54 pm

### Re: pH formula?

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

Hope it helps!

Kayla Booker 1F
Posts: 60
Joined: Wed Sep 30, 2020 9:43 pm

### Re: pH formula?

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?

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

Andy Hernandez
Posts: 56
Joined: Wed Sep 30, 2020 9:50 pm

### Re: pH formula?

The pH formula is -log[H+]

805421690
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### Re: pH formula?

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

Nicole Bruno Dis 1B
Posts: 51
Joined: Wed Sep 30, 2020 9:36 pm

### Re: pH formula?

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
Posts: 61
Joined: Wed Sep 30, 2020 10:03 pm

### Re: pH formula?

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