Difference between revisions of "PH"
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(expanding noting range explaining logarithmic nature) |
(One of these "and-milliliters-are-not-really-cc's"-type technicalities... activity, not concentration. Dump it in a footnote where it won't bother anyone) |
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pH equal to 7 is considered to be neutral. This is the pH of pure water at a temperature of 25 °C. | pH equal to 7 is considered to be neutral. This is the pH of pure water at a temperature of 25 °C. | ||
| − | pH is a logarithmic scale based on the concentration of protons(H+) in the solution. Thus, a change of pH by 1 corresponds to a change in concentration by a factor of 10. In general, the pH of most substances varies from 0 to 14 although for some extreme cases the pH can be greater than 14 or less than 0. | + | pH is a logarithmic scale. Roughly, it can be considered to be based on the concentration of protons(H+) in the solution.<ref>Actually, it is based on something called the hydrogen ion ''activity.'' Activity is approximately the same as concentration for dilute solutions in nearly pure water.</ref> Thus, a change of pH by 1 corresponds to a change in concentration by a factor of 10. In general, the pH of most substances varies from 0 to 14 although for some extreme cases the pH can be greater than 14 or less than 0. |
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| + | ==Notes and references== | ||
| + | <references/> | ||
Revision as of 15:55, March 4, 2007
For technical reasons this article is titled "PH" The title should be "pH." pH measures the acidity or basicity of a (chemical) solution.
Solutions having a pH that is less than 7 are called "acidic". Solutions having a pH greater than 7 are called "basic".
pH equal to 7 is considered to be neutral. This is the pH of pure water at a temperature of 25 °C.
pH is a logarithmic scale. Roughly, it can be considered to be based on the concentration of protons(H+) in the solution.[1] Thus, a change of pH by 1 corresponds to a change in concentration by a factor of 10. In general, the pH of most substances varies from 0 to 14 although for some extreme cases the pH can be greater than 14 or less than 0.
Notes and references
- ↑ Actually, it is based on something called the hydrogen ion activity. Activity is approximately the same as concentration for dilute solutions in nearly pure water.