The change in enthalpy (\(\Delta H\)) for an ideal gas is given by:
\[ \Delta H = n C_P \Delta T \]
where \( C_P = C_V + R \) for a monoatomic gas.
\[ C_P = 12 + 8.3 = 20.3 \text{ J K}^{-1} \text{mol}^{-1} \]
From the diagram:
\[ \Delta T = T_Z - T_X = 415K - 335K = 80K \]
\[ \Delta H = 5 \times 20.3 \times 80 \]
\[ = 8120 \text{ J} \]