Answer
$Q_i=606.8\ kJ$
Work Step by Step
From tables A-4 to A-6:
Initial ($P_1=2\ MPa, T_1=300°C$): $v_1=0.12551\ m³/kg,\ u_1=2773.2\ kJ/kg,\ h_1=3024.2\ kJ/kg$
Final ($P_2=2\ MPa, T_2=500°C$): $v_2=0.17568\ m³/kg,\ u_2=3116.9\ kJ/kg,\ h_2=3468.3\ kJ/kg$
From the material balance:
$m_e=m_1-m_2$
From $m=V_t/v,\ V_t=0.2\ m³$:
$m_1=1.594\ kg,\ m_2=1.138\ kg\rightarrow m_e=0.456\ kg$
From the energy balance:
$Q_i-m_eh_e=m_2u_2-m_1u_1$
Assuming $h_e\approx (h_1+h_2)/2=3246.2\ kJ/kg$
we get to: $Q_i=606.8\ kJ$
