n = (1.2 atm * 3.7 L) / (0.0821 L*atm/mol*K * 290 K) ≈ 0.1786 moles. Replace the supplied numbers. Ultimately, calculate the mass by multiplying the moles by the ammonia's molar mass (17 g/mol): 0.1786 moles * 17 g/mol ≈ 3.04 grams. Consequently, the ammonia gas has a mass of about 3.04 grams.

To calculate the mass of ammonia gas, use the given expression:

n = (P * V) / (R * T)

where:
P = pressure (in atm)
V = volume (in L)
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature (in K)
n = number of moles

Substituting the given values:

n = (1.2 atm * 3.7 L) / (0.0821 L·atm/mol·K * 290 K)
n ≈ 0.1786 moles

To calculate the mass, use the equation:

mass = n * molar mass

where the molar mass of ammonia (NH3) is approximately 17 g/mol:

mass = 0.1786 moles * 17 g/mol
mass ≈ 3.04 grams

Therefore, the mass of the ammonia gas is approximately 3.04 grams.