At standard temperature (STP), which is 0 degrees Celsius (273.15 Kelvin) and 1 atmosphere of pressure, the volume of 2 moles of Hydrogen gas (H2) can be calculated using the ideal gas law:

PV = nRT

Where:

- P: Pressure (in atmospheres, atm)

- V: Volume (in liters, L)

- n: Number of moles (in this case, 2 moles)

- R: Ideal gas constant (0.08206 L * atm / mol * K)

- T: Temperature (in Kelvin, K)

At STP, the pressure is 1 atm, and the temperature is 273.15 K. Substituting these values into the formula, we get:

(1 atm) * V = (2 moles) * (0.08206 L * atm / mol * K) * (273.15 K)

Solving for V, we find that the volume of 2 moles of Hydrogen at STP is approximately 44.8 liters.