According to an article dated back in February 8, 1992 which is entitled, “Science: Stardust is made of diamonds” on a website called newscientist (https://www.newscientist.com/article/mg13318073-000-science-stardust-is-made-of-diamonds/), American astronomers believed that diamonds are made in supernova explosions. It was said that the diamonds were the foundation of uncommon combinations of isotopes found in some meteorites. Donald Clayton of Clemson University in South Carolina suggested that the weightiest isotopes were more common in meteorites for the reason that the rare gases shaped in the neutron-rich outcome of a supernova explosion. Clayton also said, “the observed mixture of isotopes could have been produced only during the collapse of a massive star to form a neutron star”. This happens in a Type II explosion, for example the Supernova 1987A in the Large Magellanic Cloud. And rare gases like xenon become stuck in both weighty and light isotopes after the ejected gas from such a supernova cools down enough to create dust. The existence of the diamonds with these unusual gases in meteorites infers an alike source. Some of the carbon in the supernova fragments produces ordinary graphite dust, whereas some produces diamond dust. Considerable amount of stardust may be made of diamonds, if Clayton was not mistaken.
Answer:
The molar mass of Pb(Cr2O7)2 is 639.2 g/mol.
Answer:
The edge length of a face-centered cubic unit cell is 435.6 pm.
Explanation:
In a face-centered cubic unit cell, each of the eight corners is occupied by one atom and each of the six faces is occupied by a single atom.
Hence, the number of atoms in an FCC unit cell is:
In a face-centered cubic unit cell, to find the edge length we need to use Pythagorean Theorem:
(1)
Where:
a: is the edge length
R: is the radius of each atom = 154 pm
By solving equation (1) for "a" we have:
Therefore, the edge length of a face-centered cubic unit cell is 435.6 pm.
I hope it helps you!
The answers would be the mass before a reaction is the same as the mass after a reaction which basically means mass is conserved
Answer:
Pb: 22.4 at%
Sn: 77.6 at%
Explanation:
It is possible to find at% of Pb and Sn converting mass in moles using molar mass assuming a basis of 100g, thus:
Pb: 33.5g × (1mol / 207.2g) = <em>0.1617mol</em>
Sn: 66.5g × (1mol / 118.7g) = <em>0.5602mol</em>
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Total moles: 0.1617mol + 0.5602mol = 0.7219mol
Composition in at%:
Pb: 0.1617mol / 0.7219mol × 100 = <em>22.4 at%</em>
Sn: 0.5602mol / 0.7219mol × 100 = <em>77.6 at%</em>
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I hope it helps!
