In a #1*mg# mass of oxygen gas what is the number of #"oxygen atoms"#?

1 Answer
anor277
Feb 4, 2017

Approx, #4xx10^19# #"individual oxygen atoms........"#

Explanation:

We calculate the quotient: #"Mass"/"Molar mass"#, and get an answer in moles.

And thus #"moles of dioxygen"=(1xx10^-3*g)/(32.0*g*mol^-1)=3.1xx10^-5*mol#.

Now it is fact that #"1 mole of stuff"# contains, by definition, #"Avogadro's number"# #=# #6.022xx10^23*mol^-1#.

And thus the #"number of oxygen atoms"=2xx3.1xx10^-5*molxx6.022xx10^23*mol^-1=??#

Why did I include the #2# in that product?

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