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A pyrite cube (center) has dissolved away from a host rock, leaving behind trace gold Iron pyrite is unstable when exposed to the oxidizing conditions prevailing at the Earth's surface: iron pyrite in contact with atmospheric oxygen and water, or damp, ultimately decomposes into iron oxyhydroxides ( ferrihydrite , FeO(OH)) and sulfuric acid ( H
In this case, the pyrite has dissolved away yielding a cube shape and residual gold. This break down is the main driver of acid mine drainage. Sub-surface mining often progresses below the water table, so water must be constantly pumped out of the mine in order to prevent flooding. When a mine is abandoned, the pumping ceases, and water floods ...
Here, fresh aqua regia has been added to these NMR tubes to remove all traces of organic material. Aqua regia (/ ˈ r eɪ ɡ i ə, ˈ r iː dʒ i ə /; from Latin, "regal water" or "royal water") is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. [b] Aqua regia is a fuming liquid.
Gypsum is moderately water-soluble (~2.0–2.5 g/L at 25 °C) [13] and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures. When gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate ( bassanite , often simply called "plaster") and, if heated ...
A suspension is a heterogeneous mixture in which the solid particles do not dissolve, but get suspended throughout the bulk of the solvent, left floating around freely in the medium. [1] The internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation , with the use of certain excipients or suspending ...
Studies show that keeping your head at the appropriate height—about 2 inches (or 5 centimeters) off the bed—helps air flow into the lungs and stabilizes your respiratory function. However ...
Chemists remove gases from solvents when the compounds they are working on are possibly air- or oxygen-sensitive (air-free technique), or when bubble formation at solid-liquid interfaces becomes a problem. The formation of gas bubbles when a liquid is frozen can also be undesirable, necessitating degassing beforehand.
"The longer the retardant dries, the more difficult it is to remove completely," they cautioned. Warm water and mild detergent are effective in removing it from small surfaces, the company has said.