Answer:
Atmospheric nitrogen is not heavier than chemical nitrogen, largely because “chemical nitrogen” is ultimately derived from atmospheric nitrogen. On the other hand, you could be asking why the atomic mass of nitrogen is not the same as the mass of nitrogen gas; that's because gaseous nitrogen is diatomic, .
Explanation:
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Answer:
the speed of the earth's rotation, the tilt of the earth's axis and the directness of the sun
<span>Molds are created to achieve a
specific design of a material. These materials either came from a process of
having a higher or lower temperature. Therefore, the molder must have thermal
resistant properties. Low melting points means that the material to be shaped
came from a cooler process. Wood and metal have higher thermal conductivity and
therefore can easily be cooled. The wax can turn really hard and can be
unbreakable when present in colder materials due to the lipids present in it. Clay
however can become a mold because of its low melting point.</span>
The postulates of Dalton's theory were:
1) Elements are made of extremely small particles called atoms
2) <span>Atoms of a given element are identical in size, mass, and other properties
</span>3) <span>Atoms cannot be subdivided, created, or destroyed</span>
4) Atoms combine in whole number ratio to form compounds
5) Chemical reactions are the rearrangement of atoms
The third postulate has been disproved by modern science, in which the atom has been split and been subdivided into smaller parts such as the neutron, proton and electron, which are further subdivided into quarks, gluons, and kaons.
The second postulate was also disproved upon the discovery of isotopes.
Answer:
28g remain after 13.5 hours
Explanation:
Element decayment follows first order kinetics law:
ln[Pa-234] = -kt + ln [Pa-234]₀ <em>(1)</em>
<em>Where [Pa-234] is concentration after t time, k is rate constant in time, and [Pa-234]₀ is initial concentration</em>
Half-life formula is:
6.75 = ln2 / k
<em>k = 0.1027hours⁻¹</em>
Using rate constant in (1):
ln[Pa-234] = -0.1027hours⁻¹×13.5hours + ln [112.0g]
ln[Pa-234] = 3.332
[Pa-234] = <em>28g after 13.5 hours</em>
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