Chem: Calculate volume given molarity and pH

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SUMMARY

The discussion focuses on calculating the volume of a KOH solution required to achieve a pH of 12.5. The participant correctly derives the hydronium ion concentration as [H3O+] = 3.2 x 10^-13 mol/L and subsequently calculates the hydroxide ion concentration [OH-] to be 3.1 x 10^-2 M. Using the formula for molarity, the final volume required to dissolve 1.0 mol of KOH is determined to be 32 liters. The participant expresses uncertainty about the correctness of their solution.

PREREQUISITES
  • Understanding of pH and its relationship to hydronium ion concentration
  • Knowledge of strong base dissociation, specifically KOH
  • Familiarity with molarity calculations
  • Basic logarithmic functions and their applications in chemistry
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  • Study the relationship between pH and pOH in aqueous solutions
  • Learn about the dissociation constants of strong bases
  • Explore advanced molarity and dilution calculations
  • Investigate the implications of pH on chemical reactions and equilibria
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Winning
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Homework Statement



What volume of solution is needed to dissolve 1.0 mol of a strong base such as KOH to make a solution whose pH is 12.5?

Homework Equations



KOH_{(s)} \rightarrow K^{+}_{(aq)} + OH^{-}_{(aq)}

pH = -log[H_{3}O^{+}]

The Attempt at a Solution



I'm not going to bother with the pretty print here... sorry

12.5 = -log[H3O+]
[H3O+] = 10^-12.5
[H3O+] = 3.2 x 10^-13 mol/L

[OH-] = 10^-14/(3.2 x 10^-13) M
[OH-] = 3.1 x 10^-2 M

1.0 mol * 1 L / (3.1 x 10^-2) mol = 32 L

ans: 32 L

I feel like I'm wrong... help please.
 
Last edited:
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Winning said:
I feel like I'm wrong...

You feel wrong.
 

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