Final answer:
The new temperature of the gas, when the pressure is lowered to standard pressure while volume is constant, is approximately 17.438 Kelvin.
Step-by-step explanation:
When we talk about the relationship between gas pressure and temperature while volume is held constant, we refer to Gay-Lussac's Law, which states that the pressure of a gas is directly proportional to its absolute temperature (in Kelvin), assuming the volume doesn't change. Using the standard pressure of 1 atm for our calculations and the initial conditions provided, 30 atm of pressure and 250°C (which is 523.15 K, after converting from Celsius to Kelvin), we can set up a proportion to solve for the new temperature when the pressure is decreased to 1 atm. Now, let's do the calculation:
(Initial Pressure / Initial Temperature) = (Final Pressure / Final Temperature)
P1 / T1 = P2 / T2
30 atm / 523.15 K = 1 atm / T2
T2 = 523.15 K / 30
T2 = 17.438 K
Therefore, the new temperature of the gas when the pressure is decreased to standard pressure (1 atm) while maintaining constant volume is approximately 17.438 K.