PV = nRT

where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature.

If the volume is fixed, then we can write:

P = nRT/V

Let's calculate the initial pressure using H2 gas:

n(H2) = 2 g / 2 g/mol = 1 mol

P1 = n(H2)RT1/V

P1 = (1 mol)(0.08206 L*atm/mol*K)(273 K)/V

P1 = 22.4 atm

Now, let's calculate the final pressure using H2 and He gases:

n(total) = n(H2) + n(He) = 1 mol + 2 mol = 3 mol

P2 = n(total)RT2/V

P2 = (3 mol)(0.08206 L*atm/mol*K)(1092 K)/V

P2 = 86 atm

Therefore, the ratio of final pressure to initial pressure is:

P2/P1 = 86 atm/22.4 atm = 3.8

So the pressure increased 3.8 times.