The new volume of the bag : 747.43 ml
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature
[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
V₁=250 ml
T₁=19+273=292 K
T₂=600+273=873 K
[tex]\tt V_2=\dfrac{V_1.T_2}{T_1}\\\\V_2=\dfrac{250\times 873}{292}\\\\V_2=747.43~ml[/tex]