Heat Capacity, Cp

Consider the simple flowsheet shown in Fig. 6.2. Flow rates, temperatures, and heat duties for each stream are shown. Two of the streams in Fig. 6.2 are sources of heat (hot streams) and two are sinks for heat (cold streams). Assuming that heat capacities are constant, the hot and cold streams can be extracted as given in Table 6.2. Note that the heat capacities CP are total heat capacities and... 

For a simple A B reaction, suppose that the heat capacity Cp of A is larger than the heat capacity for B. The enthalpy of A rises more steeply with temperature increase than that of B hy the definition of heat capacity... 

The heat capacity of thiazole was determined by adiabatic calorimetry from 5 to 340 K by Goursot and Westrum (295,296). A glass-type transition occurs between 145 and 175°K. Melting occurs at 239.53°K (-33-62°C) with an enthalpy increment of 2292 cal mole and an entropy increment of 9-57 cal mole °K . Table 1-44 summarizes the variations as a function of temperature of the most important thermodynamic properties of thiazole molar heat capacity Cp, standard entropy S°, and Gibbs function - G°-H" )IT. 

Cp may be assumed to be the ideal gas heat capacity, Cp. Average errors can be expected to be less than 5 percent. 

The heat capacity of gases is essential for some process engineering design involving gas-phase chemical reactions. Here, tlie heat capacities, Cp, for gases are required to determine the heat necessary to bring the chemical compound increase to the reaction temperature. The heat capacity of a mixture of gases may he found from the heat capacities of the individual components contained in the mixtures. 

In this approach, connectivity indices were used as the principle descriptor of the topology of the repeat unit of a polymer. The connectivity indices of various polymers were first correlated directly with the experimental data for six different physical properties. The six properties were Van der Waals volume (Vw), molar volume (V), heat capacity (Cp), solubility parameter (5), glass transition temperature Tfj, and cohesive energies ( coh) for the 45 different polymers. Available data were used to establish the dependence of these properties on the topological indices. All the experimental data for these properties were trained simultaneously in the proposed neural network model in order to develop an overall cause-effect relationship for all six properties. 

Sometimes tabulated values of the mean molal heat capacities Cp (T) are more easily accessible than C (T data, with respect to a reference temperature of T = 25°C (see Table 2-45). Since Cp is defined over the range T and T, by... 

Table 25. Enthalpy, H -H0, and heat capacity, Cp, of liquid sodium...

Figure 5.1 is a graph of the specific heat capacity cp (heat capacity per gram) of aqueous sulfuric acid solutions at T — 298.15 K against A, the ratio of moles of water to moles of sulfuric acid. The values plotted were obtained from a very... 

The heat capacity (Cp and CY) also becomes infinite at the critical point.k For example, Figure 8.8 shows a graph of the heat capacity of CCF (expressed... 

Fig. 4. Heat capacity Cp of iron-epoxy particulates plotted against temperature with four different filler-volume fractions and for a particle diameter df = 0.40 x 10-3 m...

Equation 1.5 is similar in nature to the relationship between force mass and accelara-tion given by equation 1.1 with one important exception. The proportionality constant in equation 1.1 is not a function of the material concerned and it has been possible arbitrarily to put it equal to unity. The constant in equation 1.5, the specific heat capacity Cp, differs from one material to another. 

In the SI system, the unit of heat is taken as the same as that of mechanical energy and is therefore the Joule. For water at 298 K (the datum used for many definitions), the specific heat capacity Cp is 4186.8 J/kg K. 

Because inertial mass is involved in mechanical energy, the dimensions of all energy terms are M L2T 2. Inertial mass, however, is not involved in thermal energy (heat) and therefore specific heat capacity Cp has the dimensions MiL2T2/M//ff = MjM/ L2T 2 1 or according to whether energy is expressed in, joules or kilocalories, for... 

By using the simple Reynolds Analogy, obtain the relation between the heat transfer coefficient and the mass transfer coefficient for the gas phase for the absorption of a soluble component from a mixture of gases. If the heat transfer coefficient is 100 W/m2 K, what will the mass transfer coefficient be for a gas of specific heat capacity Cp of 1.5 kJ/kg K and density 1.5 kg/m- The concentration of the gas is sufficiently low for hulk flow effects to be negligible. 

Substance Molar mass, M (g-mol ) Enthalpy of formation, AHf° (kj-mol l) Gibbs free energy of formation, AGf° (kj-mol ) Molar heat capacity, Cp,m (J K -mol ) Molar entropy, 5m°(J-K -mol )... 

Stream number Type Heat capacity CP, kW/°C Ts °C T, °C Heat load kW... 

It is convenient to represent a heat exchanger network as a grid see Figure 3.24. The process streams are drawn as horizontal lines, with the stream numbers shown in square boxes. Hot streams are drawn at the top of the grid, and flow from left to right. The cold streams are drawn at the bottom, and flow from right to left. The stream heat capacities CP are shown in a column at the end of the stream lines. 

The heat capacity cp is negligible compared to the phase change enthalpy (cp AT latent heat at the phase change temperature has to be considered. 

Figure 125 shows the cooling of the semi-infinite PCM layer. Because the heat capacity cp is negligible, the temperature change from the location of the phase front at distance s to the surface is linear. The heat flux at the surface as a function of the location of the phase front is then... 

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