5 L of helium gas is at a pressure of 1.5 atm. The pressure of the gas in mm Hg is required.
This question is only about converting pressure from atm. to mm Hg.
1 atm. is equivalent to 760.001 mm Hg.
1.5 atm. is equivalent to 1.5*760.001 = 1140 mm Hg.
The pressure of the gas at 1.5 atm. is 1140 mm Hg.