Answer: 60 atm
Explanation:
Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of an ideal gas at constant volume and number of moles.
[tex]P\propto T[/tex] (At constant volume and number of moles)
[tex]{P_1\times T_1}={P_2\times T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = ?
[tex]P_2[/tex] = final pressure of gas= 100 atm
[tex]T_1[/tex] = initial temperature of gas = 500 K
[tex]T_2[/tex] = final temperature of gas = 300 K
[tex]{P_1\times 500}={100\times 300}[/tex]
[tex]P_1=60atm[/tex]
Therefore, the pressure it would exert at the working temperature if it behaved as an ideal gas is 60 atm.