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The major disadvantage with solids is that the water has to be accessible and easily brought into methanol solution. Many common substances, especially foods such as chocolate, release water slowly and with difficulty, requiring additional efforts to reliably bring the total water content into contact with the Karl Fischer reagents.
Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed as a ratio, which can range from 0 (completely dry) to the value of the materials' porosity at saturation.
Moisture analysis covers a variety of methods for measuring the moisture content in solids, liquids, or gases.For example, moisture (usually measured as a percentage) is a common specification in commercial food production. [1]
It is measured by saturating sample of soil 1 cm thick, and subjecting it to a centrifugal force of 1000 times gravity for 30 min. The gravimetric water content after this treatment is its moisture equivalent. This concept is no longer used in soil physics and has been replaced by field capacity. Lyman Briggs and Homer LeRoy Shantz (1912) found ...
Food moisture analysis is the determination of the concentration of water in a food sample. A variety of techniques may be used including Karl Fischer titration and loss on drying. Many technical standards exist which define test methods for determining moisture in different types of food.
C is the heat capacity of a body made of the material in question (J/K) n is the amount of substance in the body ; R is the gas constant (J⋅K −1 ⋅mol −1) N is the number of molecules in the body. (dimensionless) k B is the Boltzmann constant (J⋅K −1) Again, SI units shown for example.
An EPA scientist samples water in Florida Everglades. Samples of water from the natural environment are routinely taken and analyzed as part of a pre-determined monitoring program by regulatory authorities to ensure that waters remain unpolluted, or if polluted, that the levels of pollution are not increasing or are falling in line with an agreed remediation plan.
For liquid solutions, the osmotic coefficient is often used to calculate the salt activity coefficient from the solvent activity, or vice versa. For example, freezing point depression measurements, or measurements of deviations from ideality for other colligative properties, allows calculation of the salt activity coefficient through the osmotic coefficient.