Question #407ab

1 Answer
Jul 18, 2017

Answer:

We know that #N_A# ammonia molecules have a mass of #17.03*g#. And thus the number of atoms in a #4.25*g# mass of AMMONIA is #6.01xx10^23#, i.e. #"Avocado's number of atoms."#

Explanation:

We work out (i) the molar quantity of ammonia:

#=(4.25*g)/(17.03*g*mol^-1)=0.250*mol#

And (ii), we were axed for the number of ATOMS in such a molar quantity. And because there are 4 moles of atoms in EACH mole of ammonia, we get a mole of atoms as our final answer....

... #0.75xxN_A# #"hydrogen atoms"# #+# #0.25xxN_A# #"nitrogen atoms"#.

i.e. a mole of atoms in TOTAL.