Asubstance that cannot be broken down into simpler substances by chemical means. an element is composed of atoms that have the same atomic number, that is, each atom has the same number of protons in its nucleus as all other atoms of that element. today 117 elements are known, of which 92 are known to occur in nature, while the remainder have only been made with particle accelerators. eighty-one of the elements have isotopes that are stable. the others, including technetium, promethium, and those with atomic numbers higher than 83, are radioactive. see periodic table.
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Chemistry, 22.06.2019 02:20
Compared with the freezing-point depression of a 0.01 m c6h12o6 solution, the freezing-point depression of a 0.01 m nacl solution is
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Chemistry, 22.06.2019 13:00
One of the hopes for solving the world's energy problem is to make use of the fusion reaction 21h +31h --> 42he + 10n + energy how much energy is released when 1 mol of deuterium is fused with 1 mol of tritium according to the above reaction? the masses of the atoms and the neutrons are as follows: 21h = 2.0140 amu 31h = 3.01605 amu 42he = 4.002603 amu 10n = 1.008665 amu. the speed of light is 2.9979 x 108 m/s.
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Chemistry, 22.06.2019 13:30
Which of the following has wavelength longer than the wavelength of viable light? a) x rays b) gamma rays c) radios waves d) ultraviolet waves
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Asubstance that cannot be broken down into simpler substances by chemical means. an element is compo...
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