A thermodynamically closed system contains 1 kg of hydrogen. The system undergoes a reversible polytropic process with polytropic index 1.3. The work output during the process is 400 kJ. During the process, hydrogen behaves as an ideal gas with constant specific heats. The absolute value of heat transfer during the process is ______ kJ (rounded off to 1 decimal place).
Specific heat of hydrogen at constant pressure =14.56 kJ kg^-1K^-1
Specific heat of hydrogen at constant volume =10.4 kJ kg^-1K^-1