Unformatted text preview: h is around
10 Rock-solid, perhaps?
See this webpage for more information.
As of the writing of this exercise, the Wikipedia page given here states that it may not meet the “general notability
guideline” nor does it cite any references or sources. I ﬁnd this odd because it is this very usage of the decibel scale
which shows up in every College Algebra book I have read. Perhaps those other books have been wrong all along
and we’re just blindly following tradition.
11 344 Exponential and Logarithmic Functions
(c) The pH of a solution is a measure of its acidity or alkalinity. Speciﬁcally, pH = − log[H+ ]
where [H+ ] is the hydrogen ion concentration in moles per liter. A solution with a pH
less than 7 is an acid, one with a pH greater than 7 is a base (alkaline) and a pH of 7 is
regarded as neutral.
i. The hydrogen ion concentration of pure water is [H+ ] = 10−7 . Find its pH.
ii. Find the pH of a solution with [H+ ] = 6.3 × 10−13 .
iii. The pH of gastric acid (the acid in your stomach) is about 0.7. What is the corresponding hydrogen ion concentration? 6.1 Introduction to Exponential and Logarithmi...
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