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• Acid-base chemistry (14)
• Units of measure (47)
• Water quality indicators (11)

Encyclopedia: PH

pH is a measure of the acidity or alkalinity of a solution. Solutions with a pH less than 7 are considered acidic, while those with a pH greater than seven are considered basic (alkaline). pH 7 is defined as neutral because it is the pH of pure water at 25 °C. pH is formally dependent upon the activity of hydrogen^[1] ions (H⁺),^[2] but for very pure dilute solutions, the molarity may be used as a substitute with some sacrifice of accuracy.^[3] Because pH is dependent on activity, a property which cannot be measured easily or predicted theoretically, it is difficult to determine an accurate value for the pH of a solution. The pH reading of a solution is usually obtained by comparing unknown solutions to those of known pH, although there are other methods.

Translations

How to say "PH" in other languages:

	(Chinese)	PH值
	(Japanese)	水素イオン指数
	(German)	PH-Wert
	(Spanish)	PH
	(French)	Potentiel hydrogène
	(Italian)	PH

Search results

Ph

PH or ph or pH may be: In chemistry, pH is a measure of acidity Philippines (ISO country code) phot ( ph ) unit In computational complexity theory, PH is the union of all complexity classes in the polynomial hierarchy...

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Acid-base titration

An acid-base titration is a method for indicating the endpoint of a reaction. A pH indicator may be used, such as phenolphthalein, which turns (and stays) pink when a certain pH is reached or exceeded...

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Predominance diagram

A predominance diagram shows the predominant species that is present in solution at a given pH. A predominance diagram for a weak acid or weak base will include a crossover pH which is the pKa...

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Alkaliphile

Alkaliphiles Alkaliphiles live in alkaline environments like soda lakes, or alkaline soil. The pH level in alkaline substances is from about 9 to 11 on the pH scale. The alkaliphiles keep an alkaline level of about 9 pH inside the cells, but the environment has a higher level of alkalinity...

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Phile

Philes commonly refer to files about hacking in the days of BBSs. Ph is used as homage to the phone...

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PH (complexity)

In computational complexity theory, the complexity class PH is the union of all complexity classes in the polynomial hierarchy: PH is contained in the complexity classes P PP (the class of... | P-C PSPACE | PSPACE-C | EXPTIME | EXPSPACE | BQP | BPP | RP | ZPP | PCP | IP | PH...

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PH indicator

A pH indicator is a chemical compound that is added in small amounts to a solution so that the pH (acidity or alkalinity) of the solution can be determined easily. Hence a pH indicator is a chemical... depending on the pH. pH indicators themselves are frequently weak acids or bases. When introduced into a...

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Acid-free paper

Acid-free paper is paper that has had its acid removed during its production so that it has a neutral pH. Removal of acid prevents disintegration over time...

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Bromothymol blue

Bromothymol blue , also known as bromthymol blue , is a chemical indicator for weak acids and bases. Following are given its colours at different solution pH values. Alkaline (basic) - Blue (pH > 7) Neutral - Green (pH = 7) Acid - Yellow (pH < 7) The bromothymol blue acts as a weak acid in...

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Henderson-Hasselbalch equation

The Henderson-Hasselbalch equation is: It describes the derivation of pH as a measure of acidity in biological systems. See acid-base balance, acidosis, alkalosis...

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