The mass will be 4429 g
Use the ideal gas law to solve this problem:
This law specifies the possible conditions for a sample of gas, and makes it possible for us to find a fourth condition when values are given for the other three.
Here, we know the pressure, P is 135.0 atm. The volume, V is 200.0 L and the temperaure T is 24.00 °C, or better as 297K.
Thus, we can solve for the missing value, which is
You must be careful to choose a value for the gas constant
Now, multiply by the molar mass of helium (4 g) and this answer is reported as a mass.