Answer : The density of air in
and
is,
and
respectively.
Explanation :

where,
P = pressure of air = 1 atm
V = volume of air
T = temperature of air = 297 K
The conversion used for the temperature from Fahrenheit to degree Celsius is:


The conversion used for the temperature from degree Celsius to Kelvin is:


n = number of moles
m = mass of air
M = average molar mass of air = 28.97 g/mole
= density of air = ?
R = gas constant = 0.0821 L.atm/mol.K
Now put all the given values in the above formula, we get:



Now we have to calculate density in
.
Conversion used :

So,

The density of air in
is, 
Now we have to calculate density in
.
Conversion used :

So,

The density of air in
is, 
3.54g H2 means you have 3.54 / 2 = 1.77 moles of H2, which means you have 1.77*2 = 3.54 moles of H atom.
Since 1 mole of NH3 has 3 moles of H, so you can produce 3.54 / 3 moles of NH3, which is (3.54/3) * (12+3) = 17.7 grams
True would seem to be sufficient