8. What is the internal energy change when 2.0 moles of argon in a container of volume 500 cm3 is allowed to expand isothermally to 1000 cm3 at 25oC？ (A)4955 J　(B)2478 J　(C)48.9 J　(D)0 J

6. Given that the enthalpy required to convert CHCl3(g) to gaseous C, H, and Cl atoms is 1397 kJ/mol and that the dissociation enthalpy of a C-H bond is 413 kJ/mol, what is the bond dissociation enthalpy of a C-Cl bond？ (A)328 kJ/mol　(B)603 kJ/mol　(C)984 kJ/mol　(D)1397 kJ/mol