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Topic: A couple of chemistry acid/base questions  (Read 3452 times)

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Offline MarkDylews

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A couple of chemistry acid/base questions
« on: August 12, 2008, 03:14:16 PM »
My teacher didn't really explain these well. Any help appreciated. This is due tonight so please help me!

1. What is the value of the equilibrium constant (three sig figs) for the reaction of hydrofluoric acid and ammonia?
K =

Fill in the following reaction table with millimoles (to the nearest 0.01 mmol) for the reaction occurring when 44.7 mL of 0.222-M ammonia are mixed with 27.6 mL of 0.292-M hydrofluoric acid.

HF + NH3 ↔ F1- + NH41+
initial
delta
final
What is the final concentration of ammonium ion to three significant figures?

[NH41+] =

How many mmols (three sig figs) of the limiting reactant are actually present at equilibrium? Note that this value is not based on the final amount in the reaction table because the table assumes complete reaction (not an equilibrium) of the limiting reactant.



2. Consider the titration of 35.0 mL of 0.165-M of KX with 0.078-M HCl. The pKa of HX = 5.21. Give all pH values to 0.01 pH units.
a) What is the pH of the original solution before addition of any acid?

b) How many mL of acid are required to reach the equivalence point?

c) What is the pH at the equivalence point?

d) What is the pH of the solution after the addition of 37.0 mL of acid?

e) What is the pH of the solution after the addition of 88.8 mL of acid?

Thanks,
Mark Jake Dylewski

Offline Ak

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Re: A couple of chemistry acid/base questions
« Reply #1 on: August 12, 2008, 04:54:46 PM »
for the first part of 1) u need to convert the mL and M to concentrations and then use the ice chart...wiki gives an overview of it as http://en.wikipedia.org/wiki/ICE_table...this site gives you an example of how to use the ice table http://www.wwnorton.com/college/chemistry/gilbert/concepts/chapter15/ch15_4.htm


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