50.0 g of HI is injected into an evacuated 5.00-L rigid cylinder at 340 K. What is the total pressure inside the cylinder when the system comes to equilibrium

P = 2.18 atm

Explanation:

The strategy here here is to use the ideal gas law

PV = nRT

since we know the temperature, volume and the n, the number of moles is mass/MW, and R is the gas constant 0.08205 LatmK⁻¹mol⁻¹:

MW HI = 127.91 gmol⁻¹

P = (mass / MW) x R x T / V

P = (50.0 g / 127.91 gmol⁻¹) x 0.08205 LatmK⁻¹mol⁻¹ x 340 K / 5.00 L

P = 2.18 atm

(rounded to three significant figures which is the number of significant figures for temperature, mass and volume)