Calculating pH (Leaving Cert Chemistry): Flashcards

Power of hydrogen

$\text{pH} = -\log_{10}[\text{H}^+]$

$\text{pOH} = -\log_{10}[\text{OH}^-]$

$\text{pH} + \text{pOH} = 14$

Completely dissociate (break apart)

Molarity × number of $\text{H}^+$ ions released

2 $\text{H}^+$ ions per molecule

Calculate pOH first, then use $\text{pH} = 14 - \text{pOH}$

Increases by 1 unit

Only partially dissociate

How much the acid dissociates

$[\text{H}^+] = \sqrt{K_a \times M_{\text{acid}}}$

Weak acids have higher pH values

Strong acids: high; weak acids: lower

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