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The flame test carried out on a copper halide. The characteristic bluish-green color of the flame is due to the copper. A flame test is relatively quick test for the presence of some elements in a sample. The technique is archaic and of questionable reliability, but once was a component of qualitative inorganic analysis.
Copper thermite can be prepared using either copper(I) oxide (Cu 2 O, red) or copper(II) oxide (CuO, black). The burn rate tends to be very fast and the melting point of copper is relatively low, so the reaction produces a significant amount of molten copper in a very short time.
A copper wire is cleaned and heated in a Bunsen burner flame to form a coating of copper(II) oxide. It is then dipped in the sample to be tested and once again heated in a flame. A positive test is indicated by a green flame caused by the formation of a copper halide. The test does not detect fluorine/fluorides. This test is no longer ...
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Wire diameter can be as small as 20 μm (0.79 mils) and the geometry precision is not far from ± 1 μm (0.039 mils). The wire-cut process uses water as its dielectric fluid, controlling its resistivity and other electrical properties with filters and PID controlled de-ionizer units. The water flushes the cut debris away from the cutting zone.
The graphite mould is reusable many times, because the copper alloy is not as hot as the steel alloys used in rail welding. In signal bonding, the volume of molten copper is quite small, approximately 2 cm 3 (0.1 cu in) and the mould is lightly clamped to the side of the rail, also holding a signal wire in place. In rail welding, the weld ...
It can be formed by heating copper in air at around 300–800 °C: 2 Cu + O 2 → 2 CuO. For laboratory uses, copper(II) oxide is conveniently prepared by pyrolysis of copper(II) nitrate or basic copper(II) carbonate: [4] 2 Cu(NO 3) 2 → 2 CuO + 4 NO 2 + O 2 (180°C) Cu 2 (OH) 2 CO 3 → 2 CuO + CO 2 + H 2 O. Dehydration of cupric hydroxide ...
The exploding wire method or EWM is a way to generate plasma that consists of sending a strong enough pulse of electric current through a thin wire of some electrically conductive material. The resistive heating vaporizes the wire, and an electric arc through that vapor creates an explosive shockwave .