A Goodyear blimp typically contains 4770 m3 of helium (He) at an absolute pressure of 1.10 x 105 Pa. The temperature of the helium is 274 K. What is the mass (in kg) of the helium in the blimp?
This is just a case of applying the ideal gas law,
n = PV/RT.
You know the volume (V), pressure (P) and temperature (T) and can compute the number of moles of he contained, n. Each mole of heliim weighs 4.00 grams.
The gas law constant, R is
R = 8.317 Newton-meter-mole/K. If you have P in units of Pascals and T in degrees K, you will get n in moles/m^3.