Answer : The number of moles of gas present in container are 1.697 mole.
Explanation :
Using ideal gas equation,
![PV=nRT](https://tex.z-dn.net/?f=PV%3DnRT)
where,
P = pressure of gas = 74 mmHg = 0.097 atm
conversion used : (1 atm = 760 mmHg)
V = volume of gas = 500.0 L
T = temperature of gas = ![75^oC=75+273=348K](https://tex.z-dn.net/?f=75%5EoC%3D75%2B273%3D348K)
n = number of moles of gas = ?
R = gas constant = 0.0821 L.atm/mole.K
Now put all the given values in the ideal gas equation, we get the number of moles of gas in the container.
![(0.097atm)\times (500.0L)=n\times (0.0821L.atm/mole.K)\times (348K)](https://tex.z-dn.net/?f=%280.097atm%29%5Ctimes%20%28500.0L%29%3Dn%5Ctimes%20%280.0821L.atm%2Fmole.K%29%5Ctimes%20%28348K%29)
![n=1.697mole](https://tex.z-dn.net/?f=n%3D1.697mole)
Therefore, the number of moles of gas present in container are 1.697 mole.