$(1)$ \[ \begin{align} p_2 &= p_1 \frac{T_2}{T_1} \\ &=0.1 \times 10^6 \times \frac{373}{300} \\ &=0.1243 \times 10^6 \\ \therefore &=0.1243 \ \rm{MPa} \end{align} \] $(2)$ \[ \begin{align} p_2 &= p_1 \frac{T_2}{T_1} \\ &=0.1 \times 10^6 \times \frac{1273}{300} \\ &=0.4243 \times 10^6 \\ \therefore &=0.4243 \ \rm{MPa} \end{align} \] $(3)$ \[ \begin{align} m &= \frac{p_1 V_1}{R T_1} \\ &=\frac{0.1 \times 10^6 \times 1}{2.0972 \times 10^3 \times 300} \\ &=0.16047 \\ \therefore &=0.1605 \ \rm{kg} \end{align} \] $(4)$ \[ \begin{align} Q_{12} &= mc_v \Delta T \\ &=0.16047 \times 3.160 \times 10^3 \times 920 \\ \therefore &=456.4 \ \rm{kJ} \end{align} \]