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In an aqueous solution, precipitation is the "sedimentation of a solid material (a precipitate) from a liquid solution". [ 1 ] [ 2 ] The solid formed is called the precipitate . [ 3 ] In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant .
Tests that use this reagent are called Benedict's tests. A positive result of Benedict's test is indicated by a color change from clear blue to brick-red with a precipitate. Generally, Benedict's test detects the presence of aldehyde groups, alpha-hydroxy-ketones, and hemiacetals, including those that occur in certain ketoses.
When a copper wire is dipped in a silver nitrate solution, copper displaces silver, turning the solution blue and solid silver precipitates out ("silver tree"): Cu + AgNO₃ → Cu(NO₃)₂ + Ag↓ NCSSM video on single displacement reaction Formation of tin crystals as zinc displaces tin, seen under microscope.
Most base metals in acidic solution precipitate in contact with free sulfide, e.g. from H 2 S or NaHS. Solid-liquid separation after reaction would produce a base metal-free effluent that can be discharged or further treated to reduce sulfate, and a metal sulfide concentrate with possible economic value.
In chemistry, coprecipitation (CPT) or co-precipitation is the carrying down by a precipitate of substances normally soluble under the conditions employed. [1] Analogously, in medicine, coprecipitation (referred to as immunoprecipitation) is specifically "an assay designed to purify a single antigen from a complex mixture using a specific antibody attached to a beaded support".
GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.
Two solutions are prepared separately: [2] [3] Solution A: 0.02 g of thymol blue, 0.01 g cresol red and 2 mL of ethanol; Solution B: 0.8 g of sodium bicarbonate, 7.48 g of potassium chloride and 90 mL of water; Mix Solution A and B and mix 9 mL of the mixed solution to 1000 mL of distilled water.
The second part of the Winkler test reduces (acidifies) the solution. The precipitate will dissolve back into solution as the H + reacts with the O 2− and OH − to form water. MnO(OH) 2 (s) + 4 H + (aq) → Mn 4+ (aq) + 3 H 2 O(l) The acid facilitates the conversion by the brown, Manganese-containing precipitate of the Iodide ion into ...