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9.3: Apéndice C- Resumen de Ecuaciones de Conservación y Contabilidad, Conversiones de Unidades, Modelos de Propiedades, Datos de Propiedades Termofísicas

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    C.1: Ecuaciones Básicas de Conservación y Contabilidad

    Ecuaciones Básicas de Conservación y Contabilidad

    Ecuación contable para la propiedad genérica y extensa\(B\) :

    Propiedad Extensa —\(\displaystyle B_{sys} (t) = \iiint\limits_{V_{sys}} b_{(x, y, z, t)} \rho_{(x, y, z, t)} dV\)

    Ecuación Contable —\(\dfrac{dB_{sys} (t)}{dt} = \dot{B}_{in} - \dot{B}_{out} + \dot{B}_{gen} - \dot{B}_{cons}\)

    \[\underbrace{\frac{d B_{sys}}{d t}}_{\text {Accumulation}} = \underbrace{ \underbrace{\left\{\dot{B}_{in}-\dot{B}_{out}\right\}}_{\text {non-flow boundaries}} + \underbrace{\left\{\sum_{in} \dot{m}_{i} b_{i}-\sum_{out} \dot{m}_{e} b_{e}\right\}}_{\text {flow boundaries}} }_{\text {Transport}} + \underbrace{\left\{\dot{B}_{\text {gen}} - \dot{B}_{\text {cons}}\right\}}_{\text {Generation/Consumption}} \nonumber \]

    Conservación del Momentum Lineal:\(\displaystyle \quad \mathbf{P}_{sys} = \int\limits_{V_{sys}} \mathbf{V} \rho \ dV\)

    \[\frac{d \mathbf{P}_{sys}}{dt} = \sum_{j} \mathbf{F}_{\text{ext, } j} + \left\{\sum_{in} \dot{m}_{i} \mathbf{V}_{i} - \sum_{out} \dot{m}_{e} \mathbf{V}_{e} \right\} \nonumber \]

    Conservación de la Masa:\(\displaystyle \quad m_{sys} (t)=\iiint\limits_{V_{sys}} \rho_{(x, y, z, t)} \ d V\)

    \[\frac{d m_{sys}}{dt} = \sum_{in} \dot{m}_{i} - \sum_{out} \dot{m}_{e} \nonumber \]

    \[\text{where } \dot{m} = \int\limits_{A_C} \rho V_{n} \ dA_{C} = \underbrace{\rho A_{C} V_{\text{avg}}}_{\text{1-D Flow Assumption}} \quad \text{(the mass flow rate)} \nonumber \]

    Conservación del Momentum Angular:\(\displaystyle \quad \mathbf{L}_{o, \ sys} = \int\limits_{V_{sys}} (\mathbf{r} \times \mathbf{V}) \rho \ dV\)

    \[\frac{d \mathbf{L}_{o, \ sys}}{dt} = \sum_{j} \mathbf{M}_{o, \ j} + \left\{\sum_{in} \dot{m}_{i} \left(\mathbf{r}_{i} \times \mathbf{V}_{i}\right) -\sum_{out} \dot{m}_{e} \left(\mathbf{r}_{e} \times \mathbf{V}_{e} \right)\right\} \nonumber \]

    \[\text{where } \mathbf{M}_{o, j} = \mathbf{r}_{j} \times \mathbf{F}_{j} \quad \text{or} \quad M_{\text{couple, } j} \nonumber \]

    Contabilidad de Especies Químicas:\(\quad m_{j}=n_{j} M_{j}\)

    \[\text{mass} \quad \rightarrow \quad \frac{d m_{j, \ sys}}{d t} = \sum_{in} \dot{m}_{j, i} - \sum_{out} \dot{m}_{j, e} + \left(\dot{m}_{j, \ gen}-\dot{m}_{j, \ cons}\right) \nonumber \]

    \[ \text{molar} \quad \rightarrow \quad \frac{d n_{j, \ sys}}{dt} = \sum_{in} \dot{n}_{j, \ i} - \sum_{out} \dot{n}_{j, \ e} + \left( \dot{n}_{j, \ gen} - \dot{n}_{j, \ cons} \right) \nonumber \]

    Conservación de la Energía:

    \[\begin{gathered} E_{sys} = \int\limits_{V_{sys}} e \rho \ dV \quad \text { where } \quad e = u+\frac{V^{2}}{2}+gz+e_{\text {spring}} + \ldots \\ \frac{dE_{sys}}{dt} = \dot{Q}_{\text{net, in}} + \dot{W}_{\text {net, in}} + \left\{ \sum_{in} \dot{m}_{i} \left(h_{i} + \frac{V_{i}^{2}}{2} + gz_{i} \right) - \sum_{out} \dot{m}_{e} \left(h_{e} + \frac{V_{e}^{2}}{2} + gz_{e}\right) \right\} \end{gathered} \nonumber \]

    Conservación de Carga:\(\displaystyle \quad q_{sys} = \int\limits_{V_{sys}} \tilde{q} \rho \ dV\)

    \[\frac{d q_{sys}}{dt} = \sum_{in} \dot{q}_{i} - \sum_{out} \dot{q}_{e} \nonumber \]

    Contabilidad de Entropía:\(\displaystyle \quad S_{sys} = \int\limits_{V_{sys}} s \rho \ dV \quad \text{and} \quad S_{gen} \geq 0\)

    \[\frac{d S_{sys}}{dt} = \sum_{j} \frac{\dot{Q}_{j}}{T_{b, \ j}} + \left\{ \sum_{in} \dot{m}_{i} s_{i} - \sum_{out} \dot{m}_{e} s_{e}\right\} + \dot{S}_{gen} \nonumber \]

    C.2 Conversiones de Unidades

    Conversiones de unidades

    Largo

    \[\begin{aligned} & 1 \mathrm{~ft} = 12 \mathrm{~in} = 0.3048 \mathrm{~m} = 1/3 \mathrm{~yd} \\ & 1 \mathrm{~m} = 100 \mathrm{~cm} = 1000 \mathrm{~mm} = 39.37 \mathrm{~in} = 3.2808 \mathrm{~ft} \\ & 1 \mathrm{~mile} = 5280 \mathrm{~ft} = 1609.3 \mathrm{~m} \end{aligned} \nonumber \]

    Fuerza

    \[\begin{aligned} & 1 \mathrm{~N} = 1 \mathrm{~kg} \cdot \mathrm{m}/\mathrm{s}^{2} = 0.22481 \mathrm{~lbf} \\ & 1 \mathrm{~lbf} = 1 \mathrm{~slug} \cdot \mathrm{ft}/\mathrm{s}^{2} = 32.174 \mathrm{~lbm} \cdot \mathrm{ft}/\mathrm{s}^{2} = 4.4482 \mathrm{~N} \end{aligned} \nonumber \]

    Masa

    \[\begin{aligned} &1 \mathrm{~kg} = 1000 \mathrm{~g} = 2.2046 \mathrm{~lbm} \\ &1 \mathrm{~lbm} = 16 \mathrm{~oz} = 0.45359 \mathrm{~kg} \\ &1 \mathrm{~slug} = 32.174 \mathrm{~lbm} \end{aligned} \nonumber \]

    Presión

    \[\begin{aligned} & 1 \mathrm{~atm} = 101.325 \mathrm{~kPa} = 1.01325 \mathrm{~bar} = 14.696 \mathrm{~lbf}/\mathrm{in}^{2} \\ & 1 \mathrm{~bar} = 100 \mathrm{~kPa} = 10^{5} \mathrm{~Pa} \\ & 1 \mathrm{~Pa} = 1 \mathrm{~N}/\mathrm{m}^{2} = 10^{-3} \mathrm{~kPa} \\ & 1 \mathrm{~lbf}/\mathrm{in}^{2} = 6.8947 \mathrm{~kPa} = 6894.7 \mathrm{~N}/\mathrm{m}^{2} \\ & \quad \left[ \mathrm{lbf}/\mathrm{in}^{2} \text{ often abbreviated as “psi”} \right] \end{aligned} \nonumber \]

    Valores de temperatura

    \[\begin{aligned} & (\mathrm{T} / \mathrm{K}) = \left(\mathrm{T} / { }^{\circ} \mathrm{R}\right) / 1.8 \\ & (\mathrm{T} / \mathrm{K}) = \left(\mathrm{T} / { }^{\circ} \mathrm{C} \right) + 273.15 \\ & \left(\mathrm{T} / { }^{\circ} \mathrm{C} \right) = \left[ \left( \mathrm{T} /{ }^{\circ} \mathrm{F} \right) - 32 \right]/1.8 \\ & \left(\mathrm{T} / \mathrm{R} \right) = 1.8 (\mathrm{T}/\mathrm{K}) \\ & \left( \mathrm{T}/{ }^{\circ} \mathrm{R}\right) = \left( \mathrm{T}/{ }^{\circ} \mathrm{F} \right) + 459.67 \\ & \left( \mathrm{T}/{ }^{\circ} \mathrm{F} \right) = 1.8 \left( \mathrm{T}/{ }^{\circ} \mathrm{C}\right) + 32 \end{aligned} \nonumber \]

    Energía

    \[\begin{aligned} & 1 \mathrm{~J} = 1 \mathrm{~N} \cdot \mathrm{m} \\ & 1 \mathrm{~kJ} = 1000 \mathrm{~J} = 737.56 \mathrm{~ft} \cdot \mathrm{lbf} = 0.94782 \mathrm{~Btu} \\ & 1 \mathrm{~Btu} = 1.0551 \mathrm{~kJ} = 778.17 \mathrm{~ft} \cdot \mathrm{lbf} \\ & 1 \mathrm{~ft} \cdot \mathrm{lbf} = 1.3558 \mathrm{~J} \end{aligned} \nonumber \]

    Diferencias de temperatura

    \[\begin{aligned} & (\Delta \mathrm{T}/{ }^{\circ} \mathrm{R}) = 1.8 (\Delta \mathrm{T}/\mathrm{K}) \\ & (\Delta \mathrm{T}/{ }^{\circ} \mathrm{R}) = (\Delta \mathrm{T}/{ }^{\circ} \mathrm{F}) \\ & (\Delta \mathrm{T}/\mathrm{K}) = (\Delta \mathrm{T}/{ }^{\circ} \mathrm{C}) \end{aligned} \nonumber \]

    Tasa de transferencia de energía

    \[\begin{aligned} & 1 \mathrm{~kW} = 1 \mathrm{~kJ}/\mathrm{s} = 737.56 \mathrm{~ft} \cdot \mathrm{lbf}/\mathrm{s} = 1.3410 \mathrm{~hp} = 0.94782 \mathrm{~Btu}/\mathrm{s} \\ & 1 \mathrm{~Btu}/\mathrm{s} = 1.0551 \mathrm{~kW} = 1.4149 \mathrm{~hp} = 778.17 \mathrm{~ft} \cdot \mathrm{lbf}/\mathrm{s} \\ & 1 \mathrm{~hp} = 550 \mathrm{~ft} \cdot \mathrm{lbf}/\mathrm{s} = 0.74571 \mathrm{~kW} = 0.70679 \mathrm{~Btu}/\mathrm{s} \end{aligned} \nonumber \]

    Volumen

    \[\begin{aligned} & 1 \mathrm{~m}^{3} = 1000 \mathrm{~L} = 10^{6} \mathrm{~cm}^{3} = 10^{6} \mathrm{~mL} = 35.315 \mathrm{~ft}^{3} = 264.17 \mathrm{~gal} \\ & 1 \mathrm{~ft}^{3} = 1728 \mathrm{~in}^{3} = 7.4805 \mathrm{~gal} = 0.028317 \mathrm{~m}^{3} \\ & 1 \mathrm{~gal} = 0.13368 \mathrm{~ft}^{3} = 0.0037854 \mathrm{~m}^{3} \end{aligned} \nonumber \]

    Energía Específica

    \[\begin{aligned} & 1 \mathrm{~kJ}/\mathrm{kg} = 1000 \mathrm{~m}^{2}/\mathrm{s}^{2} \\ & 1 \mathrm{~Btu}/\mathrm{lbm} = 25037 \mathrm{~ft}^{2}/\mathrm{s}^{2} \\ & 1 \mathrm{~ft} \cdot \mathrm{lbf}/\mathrm{lbm} = 32.174 \mathrm{~ft}^{2}/\mathrm{s}^{2} \end{aligned} \nonumber \]

    Caudal Volumétrico

    \[\begin{aligned} & 1 \mathrm{~m}^{3}/\mathrm{s} = 35.315 \mathrm{~ft}^{3}/\mathrm{s} = 264.17 \mathrm{~gal}/\mathrm{s} \\ & 1 \mathrm{~ft}^{3}/\mathrm{s} = 1.6990 \mathrm{~m}^{3}/\mathrm{min} = 7.4805 \mathrm{~gal}/\mathrm{s} = 448.83 \mathrm{~gal}/\mathrm{~min} \end{aligned} \nonumber \]

     

    C.3 Modelos de Sustancias

    Dos Modelos de Sustancias (Relaciones Constitutivas)
      Ecuación de Estado
     

    Modelo de Gas Ideal

    con calores específicos a temperatura ambiente

    Modelo de Sustancia Incompresible

    con calores específicos a temperatura ambiente

    Se utiliza para modelar el comportamiento de gases y vapores líquidos y sólidos
    Supuestos básicos del modelo
    1. La presión, el volumen y la temperatura obedecen a la relación ideal del gas:\[PV = NR_{u}T \nonumber \]
    2. La energía interna específica depende sólo de la temperatura,\(u = u(T)\).
    3. La masa molar de un gas ideal es igual a la masa molar de la sustancia real:\[M_{\text{ideal gas}} = M_{\text{real stuff}} \nonumber \]
    4. Los calores específicos son independientes de la temperatura, es decir, son constantes.
    1. La densidad de la sustancia es una constante.
    2. La energía interna específica depende sólo de la temperatura,\(u = u(T)\).
    3. La masa molar de una sustancia incompresible es igual a la masa molar de la sustancia real:\[M_{\text{incomp substance}} = M_{\text{real stuff}} \nonumber \]
    4. Los calores específicos son independientes de la temperatura, es decir, son constantes.
    \(P \ - \ T \ - \ \rho\)y\(P \ - \ T \ - \ \upsilon\) relaciones

    \(P=\rho RT\)y\(P \upsilon = RT\)

    donde\(R = R_{u}/M\)

    \(\upsilon = 1/\rho = \text{constant}\)

    Evaluado a temperatura ambiente

    Relaciones térmicas específicas \(c_{\text{p}} - c_{\text{v}} = R; \quad k = c_{\text{p}} / c_{\text{v}}\) \(c_{\text{p}} = c_{\text{v}} = c, \text{ a constant}\)
    \(c_{\text{p}}\)y\(c_{\text{v}}\) valores Evaluado a temperatura ambiente Evaluado a temperatura ambiente
    \(\Delta u\)— energía interna específica \(\Delta u = u_{2}-u_{1} = c_{\text{v}} \left(T_{2}-T_{1}\right)\) \(\Delta u = u_{2}-u_{1} = c \left(T_{2}-T_{1}\right)\)
    \(\Delta h\)— entalpía específica \(\Delta h = h_{2}-h_{1} = c_{\text{p}} \left(T_{2} - T_{1}\right)\) \[\begin{aligned} \Delta h &= h_{2}-h_{1} \\ &= \left(u_{2}+P_{2} \upsilon\right) - \left(u_{1}+P_{1} \upsilon\right) \\ &= \left(u_{2} - u_{1}\right) + \upsilon \left(P_{2}-P_{1}\right) \\ \text{thus}& \\ \Delta h &= \Delta u + \upsilon \Delta P = c \Delta T + \upsilon \Delta P \end{aligned} \nonumber \]

    \(\Delta s\)— entropía específica

    Nota: Todas las temperaturas son valores absolutos, es decir\({ }^{\circ} \mathrm{R}\),\(\mathrm{K}\) o, en las relaciones de entropía

    \[\begin{aligned} \Delta s &= s_{2}-s_{1} \\ &= c_{\text{p}} \ln \left(T_{2}-T_{1}\right) - R \ln \left(P_{2}-P_{1}\right) \\ &= c_{\text{v}} \ln \left(T_{2} / T_{1}\right) + R \ln \left(\upsilon_{2}-\upsilon_{1}\right) \end{aligned} \nonumber \] \[\begin{aligned} \Delta s &= s_{2}-s_{1} \\ &= c \ln \left(T_{2}/T_{1}\right) \end{aligned} \nonumber \]
    Ecuación de Gas Ideal
    Bases Molares Base Masiva

    \[\begin{array}{c} PV=nRT \\ P \bar{\upsilon} = R_{u} T \quad \text{and} \quad P = \bar{\rho} R_{u} T \end{array} \nonumber \]

    \[\begin{aligned} \text{where} & \\ P &= \text{absolute pressure of gas } \left[\text{kPa or lbf} / \mathrm{ft}^{2}\right] \\ V &= \text{volume of gas } \left[\mathrm{m}^{3} \text{ or } \mathrm{ft}^{3}\right] \\ n &= \text{number of moles of gas } \left[\text{kmol or lbmol}\right] \\ R_{u} &= \text{universal gas constant (the same for every gas)} \\ &\quad\quad \left[ \mathrm{kJ}/\left(\mathrm{kmol} \cdot \mathrm{K}\right) \text{ or } \left(\mathrm{ft} \cdot \mathrm{lbf}\right) / \left(\mathrm{lbmol} \cdot { }^{\circ} \mathrm{R}\right) \right] \\ T &= \text{absolute temperature of gas } \left[\mathrm{K} \text{ or } { }^{\circ} \mathrm{R}\right] \\ \bar{\rho} &= \text{molar density} = 1/\bar{\upsilon} \ \left[\mathrm{kmol}/\mathrm{m}^{3} \text{ or } \mathrm{lbmol}/\mathrm{ft}^{3} \right] \\ \bar{\upsilon} &= \text{molar specific volume } \left[\mathrm{m}^{3}/\mathrm{kmol} \text{ or } \mathrm{ft}^{3}/\mathrm{lbmol}\right] \end{aligned} \nonumber \]

    \[\begin{array}{c} PV=mRT \\ P \upsilon = RT \quad \text{and} \quad P = \rho R T \end{array} \nonumber \]

    \[\begin{aligned} \text{where} & \\ P &= \text{absolute pressure of gas } \left[\text{kPa or lbf} / \mathrm{ft}^{2}\right] \\ V &= \text{volume of gas } \left[\mathrm{m}^{3} \text{ or } \mathrm{ft}^{3}\right] \\ m &= \text{mass of gas } \left[\mathrm{kg} \text{ or } \mathrm{lbm}\right] \\ R &= \text{specific gas constant (different for each gas)} \\ &\quad\quad \left[\mathrm{kJ} / \left(\mathrm{kg} \cdot \mathrm{K}\right) \text{ or } \left(\mathrm{ft} \cdot \mathrm{lbf}\right) / \left(\mathrm{lbmol} \cdot { }^{\circ} \mathrm{R}\right) \right] \\ T &= \text{absolute temperature of gas } \left[\mathrm{K} \text{ or } { }^{\circ} \mathrm{R}\right] \\ \rho &= \text{density} = 1/\upsilon \ \left[ \mathrm{kg}/\mathrm{m}^{3} \text{ or } \mathrm{lbm}/\mathrm{ft}^{3} \right] \\ \upsilon &= \text{specific volume } \left[ \mathrm{m}^{3}/\mathrm{kg} \text{ or } \mathrm{ft}^{3}/\mathrm{lbm} \right] \end{aligned} \nonumber \]

    \(\text{and}\)

    \[\begin{aligned} R_{u} &= 8.314 \ \frac{\mathrm{kJ}}{\mathrm{kmol} \cdot \mathrm{K}} = 8.314 \ \frac{\mathrm{J}}{\mathrm{mol} \cdot \mathrm{K}} \\ &= 1545 \ \frac{\mathrm{ft} \cdot \mathrm{lbf}}{\mathrm{lbmol} \cdot { }^{\circ} \mathrm{R}} \end{aligned} \nonumber \]

    \(\text{and}\)\[ R = \frac{R_{u}}{M} \nonumber \]

    \(\text{where}\)\[\quad M = \text{molecular weight (molar mass) of a specific gas} \nonumber \]

    Datos de Propiedades Termofísicas para Algunas Sustancias Comunes (Unidades SI)
    Gases (at\(25^{\circ} \mathrm{C}\) y\(1 \mathrm{~atm}\))
    Sustancia   Masa molar \(\dfrac{R}{\left[ \dfrac{\mathrm{kJ}}{\mathrm{kg} \cdot \mathrm{K}} \right]}\) \(\dfrac{c_{v}}{\left[ \dfrac{\mathrm{kJ}}{\mathrm{kg} \cdot \mathrm{K}} \right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{kJ}}{\mathrm{kg} \cdot \mathrm{K}} \right]}\) \(k\) \(\dfrac{T_{c}}{\mathrm{K}}\) \(\dfrac{P_{c}}{\mathrm{bar}}\)
    Acetileno \(\mathrm{C}_{2} \mathrm{H}_{2}\) \(26.04\) \(0.3193\) \(1.37\) \(1.69\) \(1.23\) \(309\) \(62.4\)
    Aire \(28.97\) \(0.2870\) \(0.718\) \(1.005\) \(1.40\) \(133\) \(37.7\)
    Amoníaco \(\mathrm{NH}_{3}\) \(17.04\) \(0.4879\) \(1.66\) \(2.15\) \(1.30\) \(406\) \(112.8\)
    Dióxido de carbono \(\mathrm{CO}_{2}\) \(44.01\) \(0.1889\) \(0.657\) \(0.846\) \(1.29\) \(304.2\) \(73.9\)
    Monóxido de carbono \(\mathrm{CO}\) \(28.01\) \(0.2968\) \(0.744\) \(1.04\) \(1.40\) \(133\) \(35.0\)
    Etanos \(\mathrm{C}_{2} \mathrm{H}_{6}\) \(30.07\) \(0.2765\) \(1.48\) \(1.75\) \(1.18\) \(305.4\) \(48.8\)
    Etileno \(\mathrm{C}_{2} \mathrm{H}_{4}\) \(28.05\) \(0.2964\) \(1.23\) \(1.53\) \(1.24\) \(283\) \(51.2\)
    Helio \(\mathrm{He}\) \(4.003\) \(2.077\) \(3.12\) \(5.19\) \(1.67\) \(5.2\) \(2.3\)
    Hidrógeno \(\mathrm{H}_{2}\) \(2.016\) \(4.124\) \(10.2\) \(14.3\) \(1.40\) \(33.2\) \(13.0\)
    Metano \(\mathrm{CH}_{4}\) \(16.04\) \(0.5183\) \(1.70\) \(2.22\) \(1.31\) \(190.7\) \(46.4\)
    Nitrógeno \(\mathrm{N}_{2}\) \(28.01\) \(0.2968\) \(0.743\) \(1.04\) \(1.40\) \(126.2\) \(33.9\)
    Oxígeno \(\mathrm{O}_{2}\) \(32.00\) \(0.2598\) \(0.658\) \(0.918\) \(1.40\) \ (154.4\ \(50.5\)
    Propano \(\mathrm{C}_{3} \mathrm{H}_{8}\) \(44.09\) \(0.1886\) \(1.48\) \(1.67\) \(1.13\) \(370\) \(42.5\)
    Refrigerante 134a \(\mathrm{C}_{2} \mathrm{F}_{2} \mathrm{H}_{2}\) \(102.03\) \(0.08149\) \(0.76\) \(0.85\) \(1.12\) \(374.3\) \(40.6\)
    Agua (Vapor) \(\mathrm{H}_{2} \mathrm{O}\) \(18.02\) \(0.4614\) \(1.40\) \(1.86\) \(1.33\) \(647.3\) \(220.9\)
    Líquidos Sólidos*
    Sustancia Temp. \(({ }^{\circ} \mathrm{C})\) \(\dfrac{\rho}{\left[ \dfrac{\mathrm{kg}}{\mathrm{m}^{3}}\right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{kJ}}{\mathrm{kg} \cdot \mathrm{K}} \right]}\) Sustancia \(\dfrac{\rho}{\left[ \dfrac{\mathrm{kg}}{\mathrm{m}^{3}}\right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{kJ}}{\mathrm{kg} \cdot \mathrm{K}} \right]}\)
    Amoníaco \(25\) \(602\) \(4.80\) Aluminio \(2,700\) \(0.902\)
    Benceno \(20\) \(879\) \(1.72\) Latón, amarillo \(8,310\) \(0.400\)
    Salmuera\((20 \% \mathrm{NaCl})\) \(20\) \(1,150\) \(3.11\) Ladrillo (común) \(1,922\) \(0.79\)
    Etanol \(25\) \(783\) \(2.46\) Concreto \(2,300\) \(0.653\)
    Alcohol etílico \(20\) \(789\) \(2.84\) Cobre \(8,900\) \(0.386\)
    Etilenglicol \(20\) \(1,109\) \(2.84\) Vidrio, ventana \(2,700\) \(0.800\)
    Queroseno \(20\) \(820\) \(2.00\) Hierro \(7,840\) \(0.45\)
    Mercurio \(25\) \(13,560\) \(0.139\) Plomo \(11,310\) \(0.128\)
    Aceite (ligero) \(25\) \(910\) \(1.80\) Plata \(10,470\) \(0.235\)
    Refrigerante 134a \(25\) \(1,206\) \(1.42\) Acero (suave) \(7,830\) \(0.500\)
    Agua \(25\) \(997\) \(4.18\) * Evaluado a temperatura ambiente.
    Valores adaptados de K. Wart, Jr. y D. E. Richards, Termodinámica, 6a ed. (McGraw-Hill, Nueva York, 1999) e Y. A. Cengul y M. A. Boles, Termodinámica, 4ta ed. (McGraw-Hill, Nueva York, 2002).
    Datos de Propiedades Termofísicas para Algunas Sustancias Comunes (Unidades USCS)
    Gases (at\(77^{\circ} \mathrm{F}\) y\(1 \mathrm{~atm}\))
    Sustancia   Masa molar \(\dfrac{R}{\left[ \dfrac{\mathrm{ft} \cdot \mathrm{lbf}}{\mathrm{lbm} \cdot { }^{\circ} \mathrm{R}} \right]}\) \(\dfrac{c_{v}}{\left[ \dfrac{\mathrm{Btu}}{\mathrm{lbm} \cdot { }^{\circ} \mathrm{R}} \right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{Btu}}{\mathrm{lbm} \cdot { }^{\circ} \mathrm{R}} \right]}\) \(k\) \(\dfrac{T_{c}}{\text{ }^{\circ} \mathrm{R}}\) \(\dfrac{P_{c}}{\mathrm{atm}}\)
    Acetileno \(\mathrm{C}_{2} \mathrm{H}_{2}\) \(26.04\) \(59.33\) \(0.328\) \(0.404\) \(1.23\) \(556\) \(61.6\)
    Aire \(28.97\) \(53.33\) \(0.171\) \(0.240\) \(1.40\) \(239\) \(37.2\)
    Amoníaco \(\mathrm{NH}_{3}\) \(17.04\) \(90.67\) \(0.397\) \(0.514\) \(1.29\) \(730\) \(111.3\)
    Dióxido de carbono \(\mathrm{CO}_{2}\) \(44.01\) \(35.11\) \(0.156\) \(0.202\) \(1.29\) \(548\) \(72.9\)
    Monóxido de carbono \(\mathrm{CO}\) \(28.01\) \(55.16\) \(0.178\) \(0.249\) \(1.40\) \(239\) \(34.5\)
    Etanos \(\mathrm{C}_{2} \mathrm{H}_{6}\) \(30.07\) \(51.38\) \(0.353\) \(0.419\) \(1.19\) \(549\) \(48.2\)
    Etileno \(\mathrm{C}_{2} \mathrm{H}_{4}\) \(28.05\) \(55.08\) \(0.294\) \(0.365\) \(1.24\) \(510\) \(50.5\)
    Helio \(\mathrm{He}\) \(4.003\) \(386.0\) \(0.744\) \(1.24\) \(1.67\) \(9.3\) \(2.26\)
    Hidrógeno \(\mathrm{H}_{2}\) \(2.016\) \(766.4\) \(2.43\) \(3.42\) \(1.40\) \(59.8\) \(12.8\)
    Metano \(\mathrm{CH}_{4}\) \(16.04\) \(96.32\) \(0.407\) \(0.531\) \(1.30\) \(344\) \(45.8\)
    Nitrógeno \(\mathrm{N}_{2}\) \(28.01\) \(55.16\) \(0.178\) \(0.248\) \(1.39\) \(227\) \(33.5\)
    Oxígeno \(\mathrm{O}_{2}\) \(32.00\) \(48.28\) \(0.157\) \(0.219\) \(1.40\) \(278\) \(49.8\)
    Propano \(\mathrm{C}_{3} \mathrm{H}_{8}\) \(44.09\) \(35.04\) \(0.355\) \(0.400\) \(1.13\) \(666\) \(42.1\)
    Refrigerante 134a \(\mathrm{C}_{2} \mathrm{F}_{4} \mathrm{H}_{2}\) \(102.03\) \(15.14\) \(0.184\) \(0.203\) \(1.10\) \(672.8\) \(40.1\)
    Agua (Vapor) \(\mathrm{H}_{2} \mathrm{O}\) \(18.02\) \(87.74\) \(0.335\) \(0.445\) \(1.33\) \(1165\) \(218.0\)
    Líquidos Sólidos*
    Sustancia Temp\(({ }^{\circ} \mathrm{F})\) \(\dfrac{\rho}{\left[ \dfrac{\mathrm{lbm}}{\mathrm{ft}^{3}} \right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{Btu}}{\mathrm{lbm} \cdot { }^{\circ} \mathrm{R}} \right]}\) Sustancia \(\dfrac{\rho}{\left[ \dfrac{\mathrm{lbm}}{\mathrm{ft}^{3}} \right]}\) \(\dfrac{c_{p}}{\left[ \dfrac{\mathrm{Btu}}{\mathrm{lbm} \cdot { }^{\circ} \mathrm{R}} \right]}\)
    Amoníaco \(80\) \(37.5\) \(1.135\) Aluminio \(170\) \(0.215\)
    Benceno \(68\) \(54.9\) \(0.411\) Latón, amarillo \(519\) \(0.0955\)
    Salmuera\((20 \% \mathrm{NaCl})\) \(68\) \(71.8\) \(0.743\) Ladrillo (común) \(120\) \(0.189\)
    Etanol \(77\) \(48.9\) \(0.588\) Concreto \(144\) \(0.156\)
    Alcohol etílico \(68\) \(49.3\) \(0.678\) Cobre \(555\) \(0.0917\)
    Etilenglicol \(68\) \(69.2\) \(0.678\) Vidrio, ventana \(169\) \(0.191\)
    Queroseno \(68\) \(51.2\) \(0.478\) Hierro \(490\) \(0.107\)
    Mercurio \(77\) \(847\) \(0.033\) Plomo \(705\) \(0.030\)
    Aceite (ligero) \(77\) \(56.8\) \(0.430\) Plata \(655\) \(0.056\)
    Refrigerante 134a \(32\) \(80.9\) \(0.318\) Acero (suave) \(489\) \(0.119\)
    Agua \(68\) \(62.2\) \(1.00\) * Evaluado a temperatura ambiente.
    Valores adaptados de K. Wart, Jr. y D. E. Richards, Termodinámica, 6a ed. (McGraw-Hill, Nueva York, 1999) e Y. A. Cengul y M. A. Boles, Termodinámica, 4ta ed. (McGraw-Hill, Nueva York, 2002).