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### 6.4

Posted: Wed Dec 04, 2019 12:04 pm
How many hydronium ions are present at any moment in 100. mL of pure water at 25 C?

### Re: 6.4

Posted: Wed Dec 04, 2019 12:11 pm
The pH of pure water is 7. The equation to find pH is pH=-log[H3O+]. Substituting 7 into the equation, you would find that the concentration of hydronium ions is 1*10^-7. Then, to find the number of ions present, you would then do the following: $\frac{1*10^-7mol}{L} (\frac{0.100L}{1})(\frac{6.022*10^{23}ions)}{mol})$