Answer
In order from smallest to largest mass:
$H_2,\ C,\ Al,\ Si,\ Na,\ Fe,\ Cl_2$
Work Step by Step
Atomic weights (g/mol): $Na: 22.990,\ Si: 28.085,\ H: 1.008$
$ Fe: 55.845,\ Al: 26.982,\ C: 12.011,\ Cl: 35.45$
a) $3.79\times10^{24}\ atoms\div(6.022\times10^{23}\ atoms/mol)\times55.845g/mol=351\ g$
b) $19.921\ mol\times 1.008 g/mol\times2=40.16\ g$
c) $8.576\ mol\times 12.011 g/mol=103.0\ g$
d) $7.4\ mol\times 28.085 g/mol=210\ g$
e) $9.221\ mol\times 22.990 g/mol=212.0\ g$
f) $4.07\times10^{24}\ atoms\div(6.022\times10^{23}\ atoms/mol)\times26.982g/mol=182\ g$
g) $9.2\ mol\times 35.45 g/mol\times2=650\ g$
In order from smallest to largest mass:
$H_2,\ C,\ Al,\ Si,\ Na,\ Fe,\ Cl_2$
