6B. 3 Volume

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Ariel Fern 2B
Posts: 90
Joined: Fri Aug 30, 2019 12:17 am

6B. 3 Volume

Postby Ariel Fern 2B » Sun Jan 19, 2020 9:32 pm

What volumes did you use to get the pH's in this problem? Wouldn't it be 0.200 L and 0.250 L due to the volumetric flasks? I'm not getting the correct pH's using those numbers though, so any help would be appreciated!

Gerald Bernal1L
Posts: 87
Joined: Thu Jul 11, 2019 12:16 am

Re: 6B. 3 Volume

Postby Gerald Bernal1L » Sun Jan 19, 2020 10:19 pm

To find the desired pH you just use the desired concentration 0.025 and you get pH of 1.6. To get the actual solution pH you multiply the molarity by the 0.200 L volume in order to find the desired moles and divide that by 0.250 L to get the new molarity/H3O+ concentration. From there you put that in the pH equation and you get pH of 1.7.

Ariel Fern 2B
Posts: 90
Joined: Fri Aug 30, 2019 12:17 am

Re: 6B. 3 Volume

Postby Ariel Fern 2B » Sun Jan 19, 2020 10:58 pm

Gerald Bernal1L wrote:To find the desired pH you just use the desired concentration 0.025 and you get pH of 1.6. To get the actual solution pH you multiply the molarity by the 0.200 L volume in order to find the desired moles and divide that by 0.250 L to get the new molarity/H3O+ concentration. From there you put that in the pH equation and you get pH of 1.7.


Thanks so much, Gerald! That makes much more sense, lol; I think I misread the problem on accident and thought they were diluting the 0.025 M solution by using the volumetric flask to fill it up to 0.200 L and 0.250 L. I didn't realize that 0.025 M was the desired molarity of the solution.


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