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Enthalpy with the

The practical application of the model is not simple, for we must relate the observed (net) activation enthalpy with the elementary quantities in equation 3.41 and these with the reaction enthalpy. However, at the very least, it stresses that only a judicious use of experimental kinetic data in solution will afford reliable thermochemical information. [Pg.46]

In order to assess steric and electronic effects on the bond enthalpies of reaction of phosphine and phosphite ligands to platinum(II), the enthalpies (AH) of reaction of these ligands L on reaction with [PtMe(PPhMe2)2(THF)]PF6 have been measured (equation 412). These authors measured the enthalpies of 34 ligands, and correlated the measured enthalpy with the ligand cone angles.1342,1343 Representative data are shown in Table 8. [Pg.447]

A principal focus of research has been to compare the experimental enthalpies with the predictions of modern electron transfer theory [5-7]. [Pg.490]

The thermodynamic parameters were calculated and are summarized in Table III. Both enthalpy and entropy decrease considerably with complex formation. Such a large decrease in enthalpy and entropy has not been found in other complex formation systems. For example, the change in enthalpy with the complex formation because of hydrophobic interactions generally is not so large and change in entropy is positive (23,24) and change in enthalpy with the complex formation in enzymatic hydrolysis of cellulose is slightly positive (25). These unusual decreases in enthalpy and entropy are inferred to be characteristics of the present complex formation system. [Pg.179]

The related enthalpies are used to match all enthalpies with the LHV related to the chemical standard state (1 bar, 25°C). The related enthalpy is defined by... [Pg.36]

Using literature data, ten Hulscher and Cornelissen (1996) calculated sorption enthalpies with the following formula ... [Pg.167]

The results of the investigation of the MoRu alloy system is thus that it seems to be impossible to reconcile theoretical and experimental values, quite independent of which theoretical method one uses. Although it is possible to get quite close to the experimental curve by using the ab initio isostructural mixing enthalpy with the CALPHAD structural energy difference, there is no obvious reason for using this method. One can also find that no reasonable (non-negative) value of the Mo... [Pg.72]

If the working fluid is steam, check whether it is superheated or saturated at the first stage by comparing the inlet specific enthalpy, with the specific enthalpy of saturated steam appropriate to the inlet pressure, hg(po. ). If Aq.i dryness fraction and equation (15.112) to estimate the isentropic index, y. [Pg.188]

From the data of [1989LAU/BRI], we have four semi-independent measnre-ments to define the three enthalpies of formation of ThF(g), ThF2(g), ThFsfg), as shown in Table VIII-2. We have used a least-square analysis to find the optimal solntions to the over-determined sets of linear equations, nsing either the second-law or the third-law enthalpies, with the results shown in Table VIII-3. [Pg.196]

PREDICTION OF LIQUID-PHASE ENTHALPIES WITH THE REDLICH-KWONG EQUATION OF STATE. [Pg.164]

Comparing the differential enthalpy with the integral enthalpy (as determined by calorimetry) provides a test for the two-state assumption for a two-state transition these enthalpies are eqnal. [Pg.245]

This expression can be integrated if we know the variations of the enthalpy with the temperature. Usually, we consider, for finite temperature ranges, that the enthalpy is constant. [Pg.159]

In order to obtain the enthalpy of formation for the dihalide series, the next calculation step was to sum the Avckf°(IH Ik 298) enthalpies with the value obtained from the monotonous curve that connects the enthalpies of formation for barium, europium, and ytterbium dihalides (Figure 27). It is noteworthy that Johansson (1979) proposed this calculation scheme for the enthalpy of the valence transition of the lanthanides at the same time as Kim and Oishi (1979) did. [Pg.320]

It is possible to integrate this expression, in the chosen convention, if we know the variations of the enthalpies with the temperature. We... [Pg.135]

The combustion enthalpy of the flare, Ac H, is the sum of both the primary anaerobic reaction enthalpy and the afterburn reaction enthalpy with the atmospheric oxygen. Thus for an Mg/Teflon /Viton (60/30/10) payload, this ideally translates into... [Pg.165]

Fig. 37 Deposition of the five detected atoms (indicated by arrows) assigned to Cn in " Ca + experiments. The dotted lines indicate the temperature gradient inside the detector array (right axis in °C). The three panels a, b, and c reflect the three different regimes in terms of temperature range inside the detector array and gas flow rates (see text). The solid red lines depict results of a Monte Carlo model prediction (left axis in rel. units) including the given experimental parameters and assuming the deposited atoms to have always an adsorption enthalpy with the Au surface of -52 kJ mol [122, 136]. The vertical dashed lines at detectors 17, 19, and 21, respectively, indicate the start of the ice layer formation toward lower temperatures corroborated by reduced resolutions in the a spectra... Fig. 37 Deposition of the five detected atoms (indicated by arrows) assigned to Cn in " Ca + experiments. The dotted lines indicate the temperature gradient inside the detector array (right axis in °C). The three panels a, b, and c reflect the three different regimes in terms of temperature range inside the detector array and gas flow rates (see text). The solid red lines depict results of a Monte Carlo model prediction (left axis in rel. units) including the given experimental parameters and assuming the deposited atoms to have always an adsorption enthalpy with the Au surface of -52 kJ mol [122, 136]. The vertical dashed lines at detectors 17, 19, and 21, respectively, indicate the start of the ice layer formation toward lower temperatures corroborated by reduced resolutions in the a spectra...
Hydrolysis enthalpy (AHhydr) [210] for starch and cryopowders in an air-dry state is recalculated for one gram of dry (anhydrous) product. In addition, the authors of [210] compared the obtained data on the hydrolysis enthalpy with the enthalpy of enzymic hydrolysis of the same components which were thermally dried and mechanically crushed. It allowed evaluating the degree of assimilation of the aforementioned products conserved using different techniques. The obtained values were compared with the enthalpy of product mixing with the water solution of NaHCOs (pH=8.3) without the enzyme (AHmix)-... [Pg.96]

FIGURE 18.12 Changes in the desorption enthalpy for mixed cations metal chloride amines. Pure metal amines are open squares, open and fQled triangles use Mg(NH3)jCl2 arid Ca(NH3),a2 as template structures respectively. The trend of increasing desorption enthalpy with the filling of the transition metal d-band is evident, the trend is also clearly visible also when doing a 1 1 mixture in both the Mg and Ca hosts (adapted from Ref. [KXl]). [Pg.516]


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