Convert A) 10 atoms of C to mol C B) 5.1x10^22 atoms Cu to grams?

1 Answer
Jul 15, 2017

Answer:

#a.# #"Moles of carbon"=("10 carbon atoms")/(6.0221xx10^23*"carbon atoms"*mol^-1)#

Explanation:

And thus #a.=6.0221xx10^-22*mol# (which is not a great molar quantity!)........

#b.# On the other hand, we know that #N_A-=6.0221xx10^23*"copper atoms"# have a mass of #63.55*g#. How do we know this?

And so we take the product............

#(5.1xx10^22*"copper atoms"xx63.55*g*mol^-1)/(6.0221xx10^23*"copper atoms"*mol^-1)......# which quotient gives an answer with units of mass as required.......

#~=5.5*g#....... Do you agree?