Hello, everyone! Today I’m taking a break from the normal Math direction of my blog and I’ve decided to take a look at applied Math in Chemistry. Along the way, we’ll be learning about a crucial concept in Math – which is logarithms. So, let’s get started!
Most of you know about the pH concept, which is a measure of whether a solution is acidic or basic. But the concept of what pH really is – in other words, what is the quantity that it measures – is relatively unknown.
pH – or potential hydrogen – measures the acidity of a substance in terms of the concentration of its hydrogen ions. In other words, the concentration of H+ ions in a substance uniquely determines its pH. In technical terms, the formula for determining the pH of any substance would be:
pH = -log10[H+]
So, we take the base-10 logarithm of the concentration of hydrogen ions, and then take the opposite of that. And we get the value of the substance’s pH.
Let me take a back step and quickly explain to you the essence of logarithms. I’m sure you have some idea of what a logarithm is, but I’ll explain to what they exactly are. I won’t indulge in the technical details, but rather explain it in a more casual way:
If you take the logarithm base x of a number y, you want to know how many times you should multiply x by itself to receive y. Obviously it won’t be an integer each and every time, because y won’t always be the perfect number. Fractional logarithms are also allowed.
So, we take the logarithm base-10 of the concentration of H+ ions. In other words, we’re looking for how many times you should multiply 10 by itself to reach the concentration of H+ ions.
After we’ve found the number, we just take the opposite of it, and we get the pH of the substance in question.
If the pH is from 0-7, the substance is acidic. Citric acid is an example of such a substance.
If the pH is 7, the substance is neutral. Pure water is an example.
If the pH is 7-14, the substance is alkaline/basic. Milk is an example.
I hope you got something from this blog post! Stay tuned for more!
Algebra Demystified 