One uranium atom has a mass of #3.95 x 10^-22# grams. How would you work out an estimate for the number of uranium atoms in 1kg of uranium?

1 Answer
May 2, 2017

Answer:

Well, we would calculate the quotient:

#(1xx10^3*g)/(3.95xx10^-22*g)=2.53xx10^24# #"uranium atoms"#

Explanation:

Alternatively, we could work out the molar quantity, knowing that #"Avogadro's number"#, #N_A# uranium atoms have a mass of #238.03*g#. We thus speak of the molar mass of uranium as #238.03*g*mol^-1#.

And thus #"moles of uranium"=(1000*g)/(238.03*g*mol^-1)=4.20*mol#.

And then multiply this molar quantity by #"the Avocado number"#:

#4.20*cancel(mol)xx6.022xx10^23*cancel(mol^-1)=??#

Should the numbers be the same? Are the numbers the same?