Step-by-step explanation:
We have to find the mass of N₂ that is present in a 20.0 L tank at 290 K and 2.75 K. To solve this problem we will use the ideal gas law formula to get the number of moles that are present, and then we will convert the number of moles of the gas into grams using the molar mass of N₂.
P * V = n * R * T
n = P * V/(R * T)
Where n is the number of moles, P is the pressure, V is the volume of the tank, R the ideal gas constant, and T is the temperature. We already know them.
P = 2.75 atm V = 20.0 L R = 0.082 atm*L/(mol*K) T = 290 K
Now we can replace these values and get the number of moles of N₂ that are present inside the tank.
n = P * V/(R * T)
n = 2.75 atm * 20.0 L/(0.082 atm*L/(mol*K) * 290 K)
n = 2.31 moles
Finally we can convert these moles into grams using the molar mass of N₂.
molar mass of N₂ = 28.0 g/mol
mass of N₂ = 2.31 moles * 28.0 g/mol
mass of N₂ = 64.7 g
Answer: There are 64.7 g present.