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 ?
According to one report, she has shown that a group mind is capable of changing the basic physical property of leaves, making plants grow twice as high as normal, altering the molecular cluster of water, raising the pH level of polluted water, lowering violence in war-torn or crime-ridden areas and improving the health of patients with diagnosed conditions.
The pH level of the target analyte is then calculated by using the three calibration parameters as
This experiment was conducted at room temperature, DO above 4 mg/L and the pH level of the influent remained stable in the 7-8 range.
There does appear to be an optimal pH level for drinking water.
Therefore, exploration of the fluoride content and pH level in popular beverages is important in preparing the safe level guidelines of fluoride concentration and pH level in beverages.
There were no significant difference between pH levels of 4 and 9 for shoot number, and pH levels of 5 and 7 for shoot length.
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.
She added that the pH level will normalize by the time the Danube -- Europe's second largest river -- reaches countries downstream, which include Croatia, Serbia, Bulgaria, Romania and Ukraine.
"With the technology we use, we can handle the PH level. Which means that everything that leaves the river Marcal from here on is under the PH level of 9.
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.
The cleaning system requires no gloves, goggles, or other protective-wear, and the pH level of the cleaning solution generally meets drain water requirements worldwide.