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The sample is allowed to stand 1 h with occasional stirring. The sample is stirred for 30 s, and the 1:1 water pH is measured. The 0.02 M (20 mL) is added to soil suspension, the sample is stirred, and the 1:2 0.01 M pH is measured (4C1a2a2).
Soil acidification is the buildup of hydrogen cations, which reduces the soil pH. Chemically, this happens when a proton donor gets added to the soil. The donor can be an acid , such as nitric acid , sulfuric acid , or carbonic acid .
Another common measure of PSA - Peroxide Oxidisable Sulfur (S POS) - is calculated as the difference between the sulfur determined via peroxide digestion (S p) and sulfur extracted with a 1 M KCl solution (S KCl). S KCl is a measure of sulfur associated with relativity soluble sulfates (e.g., gyspum and epsomite).
Heating at higher temperatures results in decomposition into ammonia, nitrogen, sulfur dioxide, and water. [17] As a salt of a strong acid (H 2 SO 4) and weak base (NH 3), its solution is acidic; the pH of 0.1 M solution is 5.5. In aqueous solution the reactions are those of NH + 4 and SO 2− 4 ions.
This page contains tables of azeotrope data for various binary and ternary mixtures of solvents. The data include the composition of a mixture by weight (in binary azeotropes, when only one fraction is given, it is the fraction of the second component), the boiling point (b.p.) of a component, the boiling point of a mixture, and the specific gravity of the mixture.
For example, to make 100 mL of 50% alc/vol ethanol solution, water would be added to 50 mL of ethanol to make up exactly 100 mL. Whereas to make a 50% v/v ethanol solution, 50 mL of ethanol and 50 mL of water could be mixed but the resulting volume of solution will measure less than 100 mL due to the change of volume on mixing, and will contain ...
By accounting for the self-ionization of water, the true pH of the solution can be calculated. For example, a 5 × 10 −8 M solution of HCl would have a pH of 6.89 when treated as a mixture of HCl and water. The self-ionization equilibrium of solutions of sodium hydroxide at higher concentrations must also be considered.
Tests for soil pH and other qualities of soil use colored indicators, and small particles (usually clay) from the soil can cloud the test mixture and make it hard to see the color of the indicator. Barium sulfate added to the mixture binds with these particles, making them heavier so they fall to the bottom, leaving a clearer solution.