pH

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pH,

range of numbers expressing the relative acidity or alkalinity of a solution. In general, pH values range from 0 to 14. The pH of a neutral solution, i.e., one which is neither acidic nor alkaline, is 7. Acidic solutions have pH values below 7; alkaline, or basic, solutions have pH values above 7. A pH value provides a measure of the hydrogen ion concentration of a solution. In pure water the concentration of hydrogen ions is equal to 0.0000001, or 10−7, moles per liter. (A mole is the amount of a substance, expressed in grams, that is equal to the molecular weight, or formula weight, of the substance.) When an acid is added to pure water, the hydrogen ion concentration increases above this level. When an alkaline substance, or base, is added to pure water, the hydrogen ion concentration decreases below this level. Once the concentration is determined, the pH value is found by taking the exponent used in expressing this concentration and reversing its sign. This is expressed as pH=−log10 [H+]. For example, if the hydrogen ion concentration of a solution is 10−4, or 0.0001, moles per liter, the pH is 4. See indicators, acid-baseindicators, acid-base,
organic compounds that, in aqueous solution, exhibit color changes indicative of the acidity or basicity of the solution. Common indicators include p-nitrophenol, which is colorless from pH 1 to 5 and yellow from p
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pH

[pē′āch]
(chemistry)
A term used to describe the hydrogen-ion activity of a system; it is equal to -log aH+; here aH+is the activity of the hydrogen ion; in dilute solution, activity is essentially equal to concentration and pH is defined as -log10[H+], where H+is hydrogen-ion concentration in moles per liter; a solution of pH 0 to 7 is acid, pH of 7 is neutral, pH over 7 to 14 is alkaline.

pH(S)

(analytical chemistry)

pH

A measure of the acidity or alkalinity of a solution; numerically equal to 7.0 for a neutral solution; the pH value increases with increasing alkalinity and decreases with increasing acidity. Also See pH value.

PH

1. On drawings, abbr. for phase.
2. Abbr. for phillips head.

phot

A unit of illumination equal to 1 lumen per square centimeter. Abbr. ph.

pH

potential of hydrogen; a measure of the acidity or alkalinity of a solution equal to the common logarithm of the reciprocal of the concentration of hydrogen ions in moles per cubic decimetre of solution. Pure water has a pH of 7, acid solutions have a pH less than 7, and alkaline solutions a pH greater than 7

PH

(tool)
The tool for looking up people in Eudora on the Macintosh. Equivalent to Unix's finger service.

pH

(2)

ph

(networking)
The country code for the Philippines.
References in periodicals archive ?
The Dubai Central Laboratory carried out tests for the products under question, and confirmed that the pH levels were within the acceptable percentage.
For each sample the fluoride content and pH level were measured in triplicate.
5 was significantly more effective than the other pH levels for both shoot production and shoot growth of Almond (Amygdalus communis L.
Chef Sal explains that if there is too much alkaline ash in our bodies that makes our pH levels rise, we can end up with a condition known as alkalosis.
As it is seen in the figures, a decline in pH level would lead in an increase in Absorbable Cadmium in the soil, but this is not true for the depth factor.
Which means that everything that leaves the river Marcal from here on is under the PH level of 9.
The lower-than-originally-reported pH level and fast-moving currents make officials optimistic that a natural disaster could be avoided, she said.
Summary: TEHRAN (FNA)- Research results by a unique 'natural laboratory' in the Mediterranean Sea working on the effects of rising carbon dioxide levels on life in the oceans, showed a bleak future for marine life as ocean acidity rises, and suggested that similar lowering of ocean pH levels may have been responsible for massive extinctions in the past.
coli K12 at all pH levels fitted well to a first-order kinetic model.
The normal pH level is then restored and the garments are dried.
Fungitrol is completely water-based, has a mild pH level, contains no heavy metals or formaldehydes, and is EPA-registered.
The dissolved oxygen is monitored, the pH level is monitored, the flow is monitored, and the temperate of the organic waste liquids and solids in the collection vessel are all monitored and data is generated therefrom.