Volume, molar

Values of molar volumes can be calculated from densities measured for the liquid salt, or can be calculated as for hypothetical subcooled liquid at 298.15 K using the group contribution method [47]. As expected, the molar volumes of 1,3-dialkylimidazolium salts and quaternary ammonium salts increase progressively as the length of alkyl chain of the substituent increases. Some molar volumes values at 298.15 K are listed in Table 1.3. 

The molar volumes at higher temperatures and the influence of the increasing temperature can be shown for N-butylpyridinium tetrafluoroborate. 

A gram mole of any gas at S.T.P. i.e. standard temperature and pressure (273 K and 760 mm Hg) occupies a volume of 22.4 litres. This is the molar volume. Thus 2 gm of hydrogen or 32 gm of oxygen will occupy a volume of 22.4 litres at S.T.P. 

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The virial equation of state is a power series in the reciprocal molar volume or in the pressure ... 

Since we make the simplifying assumption that the partial molar volumes are functions only of temperature, we assume that, for our purposes, pressure has no effect on liquid-liquid equilibria. Therefore, in Equation (23), pressure is not a variable. The activity coefficients depend only on temperature and composition. As for vapor-liquid equilibria, the activity coefficients used here are given by the UNIQUAC equation. Equation (15). ... 

C. These values are su but are not reliable for high accuracy in molar volumes. 

T were eliminated beyond that point, the vapor-phase correction, as calculated here, is inadequate and the liquid molar volume is no longer constant with pressure. 

VSTR is useful for estimating partial molar volumes at infinite dilution but is not used here because of Equation (4-17)... 

Subroutine MVOLM. MVOLM calculates the liquid molar volume at a given temperature using the modified Rackett equation... 

Spencer and Danner, 1972). This equation has been further modified by O Connell for reduced temperatures greater than 0.75. The saturated-liquid molar volume is given by the equation... 

ZRA - PACKET PARAMETER FOR SATURATED LIQUID MOLAR VOLUME CORRELATION... 

SATURATED LIQUID MOLAR VOLUME, CC/GR-MOLE ZERO PRESS REF FUGACITY IF 1VAP.LE.2 OR VA OR PRESS IP lVAP.f O.3 K-FAC TOR... 

PURE calculates pure liquid standard-state fugacities at zero pressure, pure-component saturated liquid molar volume (cm /mole), and pure-component liquid standard-state fugacities at system pressure. Pure-component hypothetical liquid reference fugacities are calculated for noncondensable components. Liquid molar volumes for noncondensable components are taken as zero. 

Standard-state fugacities at zero pressure are evaluated using the Equation (A-2) for both condensable and noncondensable components. The Rackett Equation (B-2) is evaluated to determine the liquid molar volumes as a function of temperature. Standard-state fugacities at system temperature and pressure are given by the product of the standard-state fugacity at zero pressure and the Poynting correction shown in Equation (4-1). Double precision is advisable. 

VIP(I) Vector (length 20) of saturated liquid molar volumes (cm / mole) for condensable components for noncondensable components Vip(i) = 0 (I = 1,N). 

The pseudocritical molar volume of a mixture is obtained by weighting the... 

The critical molar volume is defined using the acentric factor by the following, relations . 

The molar volume characteristics, V, for petroleum fractions and hydrocarbons can be obtained from the known density at temperature T ... 

V, = molar volume of component i Xj, = volume fraction of component i Xj = mole fraction of component i l = conductivity of the component i in the liquid state A, = conductivity of the mixture in the liquid state... 

The molar volume of the liquid is easily estimated by one of the equations given in article 4.3.1.1. 

Fugacity is expressed as a function of the molar volume, the temperature, the parameters for pure substances Oj and h, and the binary interaction coefficients )... 

If the variation of density and hence molar volume with temperature is small, it follows from Eqs. Ill-10 and III-8 that E will be nearly temperature-independent. In fact, Eq. Ill-11 with n = 1 may be written in the form... 

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