3.7 degree celsius
According to ideal gas equation;
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]where:
• P1 and P2 are the initial and final pressure
,• V1 and V2 are the initial and new volume
,• T1 and T2 are the initial and final temperature
Given the following parameters
[tex]\begin{gathered} P_1=6atm \\ V_1=2L \\ T_1=27^0C \\ P_2=2.5atm \\ V_2=0.66L \end{gathered}[/tex]Required
Final temperature T2
Substitute
[tex]\begin{gathered} T_2=\frac{P_2V_2T_1}{P_1V_1} \\ T_2=\frac{2.5\times0.66\times27}{6\times2} \\ T_2=\frac{44.55}{12} \\ T_2\approx3.7^0C \end{gathered}[/tex]Therefore the new temperature in Celsius is 3.7 degree celsius