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Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III–V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the ...
The Marsh test treats the sample with sulfuric acid and arsenic-free zinc. Even if there are minute amounts of arsenic present, the zinc reduces the trivalent arsenic (As 3+). Here are the two half-reactions: Oxidation: Zn → Zn 2+ + 2 e − Reduction: As 2 O 3 + 12 e − + 6 H + → 2 As 3− + 3 H 2 O. Overall, we have this reaction:
In its standard state arsine is a colorless, denser-than-air gas that is slightly soluble in water (2% at 20 °C) [1] and in many organic solvents as well. [citation needed] Arsine itself is odorless, [5] but it oxidizes in air and this creates a slight garlic or fish-like scent when the compound is present above 0.5 ppm. [6]
The Lower Paleolithic period lasted over 3 million years, during which there many human-like species evolved including toward the end of this period, Homo sapiens.The original divergence between humans and chimpanzees occurred 13 (), however interbreeding continued until as recently as 4 Ma, with the first species clearly belonging to the human (and not chimpanzee) lineage being ...
An image from John Dalton's A New System of Chemical Philosophy, the first modern explanation of atomic theory.. This timeline of chemistry lists important works, discoveries, ideas, inventions, and experiments that significantly changed humanity's understanding of the modern science known as chemistry, defined as the scientific study of the composition of matter and of its interactions.
Space technology is technology for use in outer space. Space technology includes space vehicles such as spacecraft , satellites , space stations and orbital launch vehicles ; deep-space communication ; in-space propulsion ; and a wide variety of other technologies including support infrastructure equipment, and procedures .
Modern archaeologists discovered that bronze-tipped crossbow bolts at the tomb of Qin Shi Huang showed no sign of corrosion after more than 2,000 years, because they had been coated in chromium. [12] [13] Chromium was not used anywhere else until the experiments of French pharmacist and chemist Louis Nicolas Vauquelin (1763–1829) in the late ...
The programme carried out six crewed spaceflights between 1961 and 1963. The program was the first program to put humans into space, with Yuri Gagarin becoming the first man in space on April 12, 1961, aboard the Vostok 1. [79] Gherman Titov became the first person to stay in orbit for a full day on August 7, 1961, aboard the Vostok 2. [80]