Explanation:
A)
We know, each mole contains [tex]N_A=[/tex] [tex]6.023 \times 10^{23}[/tex] atoms.
It is given that mass of one oxygen atom is m= [tex]2.66\times 10^{-23}\ g[/tex].
Therefore, mass of one mole of oxygen, [tex]M=m\times N_A[/tex].
Putting value of n and [tex]N_A[/tex],
[tex]M=2.66\times 10^{-23}\times 6.023\times 10^{23} \ gm\\M=16.0\ gm[/tex]
B)
Given,
Mass of water in glass=0.050 kg = 50 gm.
From above part mass of one mole of oxygen atoms = 16.0 gm.
Therefore, number of mole of oxygen equivalent to 50 gm oxygen[tex]=\dfrac{50}{16}=3.1 \ moles.[/tex]
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Avogadro's number
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