The correct description for an atom of helium would be option C. An atom of helium has its valence electrons in its first energy level, it wouldn't and can't satisfy the Octet rule as it only has 2 electrons, but with 2, it has a full shell, as the first energy level can hold only 2 electrons.
Answer
pOH = 4.1
Explanation
<em>Given:</em>
pH = 9.9
<em>Required</em>: The concentration of OH-
Solution
pH + pOH = 14
9.9 + pOH = 14
pOH = 14-9.9
pOH = 4.1
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Answer: 1:4.69
Explanation:
The ratio can be expressed as:
Ua/Ub= √(Mb/Ma)
Where Ua/Ub is the ratio of velocity of hydrogen to carbon dioxide and Ma is the molecular mass of hydrogen gas= 2
Mb is the molecular mass of CO2 = 44
Therefore
Ua/Ub= √(44/2)
Ua/Ub = 4.69
Therefore the ratio of velocity of hydrogen gas to carbon dioxide = 1:4.69
which implies hydogen is about 4.69 times faster than carbon dioxide.