A 3.00- L

flask is filled with gaseous ammonia, NH3
. The gas pressure measured at 20.0 ∘C
is 2.05 atm
. Assuming ideal gas behavior, how many grams of ammonia are in the flask?
Express your answer to three significant figures and include the appropriate units.

1 answer

To solve this problem, we can use the ideal gas law equation:

PV = nRT

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

First, we need to convert the temperature from Celsius to Kelvin:

T(K) = 20.0 + 273 = 293 K

Now we can rearrange the ideal gas law equation to solve for the number of moles:

n = (PV) / (RT)
n = (2.05 atm * 3.00 L) / (0.0821 L*atm/mol*K * 293 K)
n ≈ 0.2508 mol

Now we can calculate the molar mass of ammonia (NH3):

N = 14.01 g/mol
H = 1.01 g/mol
Therefore, the molar mass of NH3 = 14.01 g/mol + 3(1.01 g/mol) = 17.03 g/mol

Now we can calculate the mass of ammonia in the flask:

mass = number of moles * molar mass
mass = 0.2508 mol * 17.03 g/mol = 4.27 g

Therefore, there are approximately 4.27 grams of ammonia in the flask.