Chapter 5 - Mass and Energy Analysis of Control Volumes - Problems - Page 262: 5-114

$Q_o=3.5\ kJ$

From the material balance: $m_i=m_2$ From the energy balance: $Q_i+m_ih_i=m_2u_2$ $Q_i=m_2(u_2-h_i)$ For ideal gases: $P_2V=mRT_2$ Given $P_2=100\ kPa,\ V_t=0.035\ m³,\ R=0.287\ kJ/kg.K,\ T_2=295\ K$: $m_2=0.04134\ kg=m_i$ With $T_i=T_2$: $h_i=295.17\ kJ/kg,\ u_2=210.49\ kJ/kg$ Hence $Q_i=-3.5\ kJ \rightarrow Q_o=3.5\ kJ$