Ha bah, you young students make a mountain from a molehill. Take your Ka and your initial acid concentration, C. The [H⁺] is roughly √(Ka•C). Then pH = -log of that. Only works if the acid is truly weak.
I do the same with our river water tests—the quick maths with a worn calculator tells me if the sample is safe enough, before the fancy report is due.
But remember, this shortcut is like assuming the evening clinic will be open. If the acid is too strong or too dilute, your approximation breaks down, and you’re left waiting for the full, tedious calculation.
#education#class
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