pH formula?

Moderators: Chem_Mod, Chem_Admin

Saleha_Mian_3E
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

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
Posts: 61
Joined: Fri Sep 28, 2018 12:27 am

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
Posts: 30
Joined: Fri Sep 28, 2018 12:16 am

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
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am
Been upvoted: 1 time

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

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

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
Posts: 72
Joined: Fri Sep 28, 2018 12:17 am

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
Posts: 49
Joined: Fri Sep 28, 2018 12:24 am

Re: pH formula?

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

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

NRodgers_1C
Posts: 54
Joined: Thu Jul 25, 2019 12:15 am

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

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

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 1A
Posts: 54
Joined: Fri Aug 02, 2019 12:15 am
Been upvoted: 1 time

Re: pH formula?

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

pH=-log[h+]

preyasikumar_4E
Posts: 50
Joined: Fri Aug 09, 2019 12:17 am

Re: pH formula?

Postby preyasikumar_4E » 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
Posts: 61
Joined: Sat Jul 20, 2019 12:17 am

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
Posts: 50
Joined: Wed Sep 18, 2019 12:15 am

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
Posts: 64
Joined: Wed Sep 18, 2019 12:18 am

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
Posts: 52
Joined: Thu Jul 25, 2019 12:16 am

Re: pH formula?

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

pH=-log[H3O+]

Callum Guo 1A
Posts: 54
Joined: Fri Aug 02, 2019 12:15 am
Been upvoted: 1 time

Re: pH formula?

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

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

AveryAgosto
Posts: 51
Joined: Wed Sep 18, 2019 12:16 am

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

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
Posts: 50
Joined: Wed Sep 18, 2019 12:16 am
Been upvoted: 1 time

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 4G
Posts: 51
Joined: Thu Jul 25, 2019 12:17 am

Re: pH formula?

Postby Leyna Dang 4G » 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.


Return to “Calculating the pH of Salt Solutions”

Who is online

Users browsing this forum: No registered users and 1 guest