To find the mass of ammonia gas in the given sample, you can first use the Ideal Gas Law, which is formulated as PV = nRT. Rearranging this equation allows you to solve for the number of moles (n):
\[ n = \frac{PV}{RT}. \]
Using the provided values (P = 1.2 atm, V = 3.7 L, R = 0.0821 L·atm/(mol·K), and T = 290 K), you can calculate the number of moles of ammonia. Once you have the number of moles, multiply it by the molar mass of ammonia (approximately 17 g/mol) to find the mass.
Now, let's calculate the number of moles:
\[ n = \frac{(1.2 , \text{atm}) \times (3.7 , \text{L})}{(0.0821 , \text{L·atm/(mol·K)}) \times (290 , \text{K})} \]
Calculating the denominator:
\[ 0.0821 \times 290 \approx 23.877. \]
Now, substituting back into the equation for n:
\[ n \approx \frac{(1.2 \times 3.7)}{23.877} \approx \frac{4.44}{23.877} \approx 0.186. \]
Now, to find the mass:
\[ \text{mass} = n \times \text{molar mass} = 0.186 , \text{mol} \times 17 , g/mol \approx 3.162 , g. \]
Thus, the mass of the ammonia gas sample is approximately 3.16 g.