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CHM1 Example1C18 Collection

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Oct 18, 2019, 1:17:50 AM
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Example 1

I am not recording a livescribe for this problem as it follows closely previous problems.

Solution:
A Because sodium formate is a strong electrolyte, it ionizes completely in solution to give formate and sodium ions. The Na+ ions are spectator ions, so they can be ignored in the equilibrium equation. Because water is both a much weaker acid than formic acid and a much weaker base than formate, the acid–base properties of the solution are determined solely by the formic acid ionization equilibrium:

/attachments/1a0e9666-f145-11e9-8682-bc764e2038f2/Example_1.png

The initial concentrations, the changes in concentration that occur as equilibrium is reached, and the final concentrations can be tabulated.

HCO2H(aq)?H+(aq)+HCO2?(aq)
[HCO2H] [H+] [HCO2?]
initial 0.150 1.00 × 10?7 0.100
change ?x +x +x
final (0.150 ? x) x (0.100 + x)

B We substitute the expressions for the final concentrations into the equilibrium constant expression and make our usual simplifying assumptions, so

/attachments/1a0e9666-f145-11e9-8682-bc764e2038f2/Example_1_2.png
/attachments/1a0e9666-f145-11e9-8682-bc764e2038f2/Example_1_3.png
/attachments/1a0e9666-f145-11e9-8682-bc764e2038f2/Example_1_4.png

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