Answer
a) $3.32\times10^{23} atoms Ne$
b) $5.40 moles Ar$
c) $1.07\times10^{24} atoms Xe$
d) $1.79\times10^{-4} moles He$
Work Step by Step
Using Avagadro's Number, we can simply convert between atoms and moles as shown below:
a) $0.552 moles Ne\times\frac{6.023\times10^{23} atoms}{1 mole} = 3.32\times10^{23} atoms Ne$
b) $3.25\times10^{24} atoms Ar \times\frac{1 mole}{6.023\times10^{23} atoms} = 5.40 moles Ar$
c) $1.78moles Xe\times\frac{6.023\times10^{23} atoms}{1 mole} = 1.07\times10^{24} atoms Xe$
d) $1.08\times10^{20} atoms He \times\frac{1 mole}{6.023\times10^{23} atoms} = 1.79\times10^{-4} moles He$