Unit 7: Equilibrium And Acids

Section 7: More Misc Facts About Acids And Bases

Water Plays A Role

pH Scale

Conclusion

Water Plays A Role

I hope you have noticed that in most of the reactions tht we have talked about, water as the substance thtt breaks up the acid and also, many of the acids and ions are in aqueous states. And, this is the case for many of the acid-base reactions, and this is good because it helps us make a few generalities.

First, the dissociatin constant for water (K_w) is equal to:

also we know that in a neutral solution, we know that the H⁺ concentration is equal to 1.0 * 10^-7 and the OH^- concentration is equal to 1.0 * 10^-7, so by doing some math, we can solve for K_w.

This constant can be applied to all reactions involving aqueous solutions, and it will become the basis for the pH scale.

pH Scale

The pH scale is an easy way to classify how strong an acid or a base is. The pH scale is a scale from 0 to 14. On the scale, 0 is the strongest acid, 14 is the strongest base, and a neutral solution is located at 7. So if you know that substance had a pH of 6, you would know tha it was a weak acid. If you were given a substance with a pH of 13, you would know that it was a strong base. Also, if you were given the H⁺ concentration of an acid or base you can use the below formula to find the pH for that substance.

If you were given the OH^- concentration of an acid or base, you would have to use the below equation.

Conclusion

This is about as much informatin as we can give at this time without going into the math behind acids and bases. From here on, you have gotten into the middle of college level chemistry, so take pride in that!