To convert atmospheres (atm) to millimeters of mercury (mm Hg), you can use the following conversion factor:

1 atm = 760 mm Hg

So, to find the pressure in mm Hg of a gas at 2 atm, you can multiply 2 atm by the conversion factor:

2 atm * 760 mm Hg / atm = 1520 mm Hg

Therefore, the pressure of a gas at 2 atm is 1520 mm Hg.