Total Energy Change in Sodium Bicarbonate Decomposition

In an isolated system, a 10.0 g sample of solid sodium bicarbonate (NaHCO₃) is heated to a temperature of 300 °C. During the process, sodium bicarbonate undergoes decomposition according to the reaction:

2 NaHCO₃(s) → Na₂CO₃(s) + CO₂(g) + H₂O(g)

The standard enthalpy change (ΔH°) for this reaction is 128 kJ/mol. Assume that the molar mass of NaHCO₃ is 84 g/mol. Calculate the total energy change (in kJ) when the entire sample is completely decomposed.