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Topic: How do i do these?  (Read 5193 times)

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dogmattie

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How do i do these?
« on: February 06, 2006, 04:32:14 PM »
My first question is....8.00mmoles of LiOH dissolved in 100mL are titrated with .1000M HCL. Calculate the pH at equivalence point, and the pH when an additional 2mL of HCL have been added after the equivalence point.

-At the equivalence point isn't the number of moles equal to the number of moles of HCL.  I am getting some wierd numbers and thought you could help

My next question...3.2 grams fo acetic acid is dissolved in 200mL of water.  What is the pH of the solution at equilibrium? What is the pOH? The pKa of acetic acid is 4.756 and the MW is 60.021.

-I figured out the Ka and used x^2/c-x=Ka but I got a pH of 2.7.  That seems way to high for a weak acid.

Can you help me?

Offline Borek

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Re:How do i do these?
« Reply #1 on: February 06, 2006, 04:51:16 PM »
My first question is....8.00mmoles of LiOH dissolved in 100mL are titrated with .1000M HCL. Calculate the pH at equivalence point, and the pH when an additional 2mL of HCL have been added after the equivalence point.

http://www.chembuddy.com/?left=pH-calculation&right=titration-curves-calculation

Read down the page, as the beginning is about more sophisticated methods that you need.

Quote
My next question...3.2 grams fo acetic acid is dissolved in 200mL of water.  What is the pH of the solution at equilibrium? What is the pOH? The pKa of acetic acid is 4.756 and the MW is 60.021.

http://www.chembuddy.com/?left=pH-calculation&right=pH-weak-acid-base

2.67 is not too high for a weak acid ;)
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