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$$
\text { Which has the capability to produce the most work in a closed system- } 1 \text { kg of steam at } 800 \text { kPa }
$$

$$
\text { and } 180^{\circ} \mathrm{C} \text { or } 1 \mathrm{kg} \text { of } \mathrm{R}-134 \mathrm{a} \text { at } 800 \mathrm{kPa} \text { and } 180^{\circ} \mathrm{C} \text { ? Take } \mathrm{T} 0=25^{\circ} \mathrm{C} \text { and } \mathrm{PQ}=100 \mathrm{kPa}
$$

$$
\text { Steam }:
$$

$$
\left.\begin{array}{l}{P=800 \mathrm{kPa}} \\ {T=180 \mathrm{c^{\circ}}}\end{array}\right] \rightarrow A-4 
$$$$
\begin{array}{l}{u=2544.7 \mathrm{kJ} / \mathrm{kg}} \\ {v=0.2472 \mathrm{m^3} / \mathrm{kg}} \\ s=6.7155 kJ/kg.k\end{array}
$$

$$
\left.\begin{array}{l}{T_{0}=25 c^{\circ}} \\ {P_{0}=100 \mathrm{KPa}}\end{array}\right] \rightarrow A-4
$$$$
\begin{array}{l}{u_0=u_{f@25 c^{\circ}}=104.83 \mathrm{kJ} / \mathrm{kg}} \\ {v_0=v_{f@25 c^{\circ}}=0.001003} \\ s_0=s_{f@25c^{\circ}}=0.3672\end{array}
$$

$$
\Phi=m\left[u-u_0+P_{0}\left(v-v_{0}\right)-T_{0}\left(s-s_{0}\right)\right]
$$

$$
=1[2594.7-104.83+100(0.2472-0.001003)-298(6.7155-0.3672)]
$$

$$
=622.7 \mathrm{KJ}
$$

$$
R-1349
$$

$$
\left.\begin{array}{l}{P=800 \mathrm{kPa}} \\ {T=180 \mathrm{c^{\circ}}}\end{array}\right]\rightarrow A- 13
$$$$
\begin{array}{l}{u=386.99 \mathrm{kJ/kg}} \\ {v=0.044554 \mathrm{m^3/kg}} \\ s=1.3327 kJ/kg.k\end{array}
$$

$$
\begin{array}{l}{T_{0}=25{c^{\circ}}} \\ {P_{0}=100 \mathrm{kpa}}\end{array}]\rightarrow A-11
$$$$
\begin{array}{l} {u_{0}=u_{f@25c^{\circ}}=85.85} \\ {v _{0}=v_{f@25c^{\circ}}=0.0008286} \\ {s_0=s_{f@25c^{\circ}}=0.32432}\end{array}
$$

$$
\Phi=m\left[U-U_{0}+P_{0}\left(V-V_{0}\right)-T_{0}\left(S-S_{0}\right)\right]
$$

$$
=1[386.99-85.85+100(0.044554-0.0008286)-298(1.3327-0.32432)]
$$

$$
=5.02 kJ
$$

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