Assuming that the gas is ideal, use Charles' Law to relate volume and temperature at constant pressure.[tex]\frac{V1}{T1} =\frac{V2}{T2}\\\\V1 = 400mL\\T1 = 225+273.15=498.15K\\V2 = ?\\T2 = 127+273.15=400.15K\\\\\frac{400}{498.15} =\frac{V2}{400.15}\\\\\\V2 = 321.3088427mL[/tex]