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Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it ...
Accuracy measures how close a given set of observations are to their true value. Precision measures how close the observations are to each other. Accuracy and precision of observations lying on a bell curve. In the language of statistics: Accuracy is a description of systematic errors, a measure of bias. Precision is a description of random ...
If the instrument has a needle which points to a scale graduated in steps of 0.1 units, then depending on the design of the instrument it is usually possible to estimate tenths between the successive marks on the scale, so it should be possible to read off the result to an accuracy of about 0.01 units.
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Accepted and experimental value. In science, and most specifically chemistry, the accepted value denotes a value of a substance accepted by almost all scientists and the experimental value denotes the value of a substance's properties found in a localized lab.
In chemistry, the law of definite proportions, sometimes called Proust's law or the law of constant composition, states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation. For example, oxygen makes up about 8 / 9 of the mass of any sample of ...
Analytical chemistry consists of classical, wet chemical methods and modern, instrumental methods. [2] Classical qualitative methods use separations such as precipitation, extraction, and distillation. Identification may be based on differences in color, odor, melting point, boiling point, solubility, radioactivity or reactivity.
t. e. Greek letters are used in mathematics, science, engineering, and other areas where mathematical notation is used as symbols for constants, special functions, and also conventionally for variables representing certain quantities. In these contexts, the capital letters and the small letters represent distinct and unrelated entities.