Coefficient of volume expansion 1.9

Thermal Expansion Coefficient for Liquids The coefficient of volume expansion for liquids is the ratio of the change in volume per degree to the volume at -17.8°F (0°C). The value of the coefficient varies with temperature. 

Figure 8. The pressure dependence of the coefficient of volume expansions at various temperatures.

THERMAL EXPANSION COEFFICIENT. The change in volume per unit volume per degree change in temperature (cubical coefficient). For isotropic solids the expansion is equal in all directions, and the cubical coefficient is about three times the linear coefficient of expansion. These coefficients vary with temperature, but for gases at constant pressure the coefficient of volume expansion is nearly constant and equals 0.00367 for each degree Celsius at any temperature. 

Consider a cubic element within a material of volume V = lxlylz- Substituting into the definition of coefficient of volume expansion and using the product rule ... 

Since only the pressure is being measured directly, the volume Vmust remain constant or else vary in a known way with the temperature (and pressure). If a is the coefficient of linear thermal expansion of the material from which the bulb is constructed, the coefficient of volume expansion is 3a. If this is assumed constant with temperature, we can write... 

The coefficient of volume expansion is a nieasurc of the change in volume of a substance with temperature at constant pressure. 

C Consider two fluids, one with a large coefficient of volume expansion and the other with a small one. In what fluid will a hot surface initiate stronger natural convection currents Why Assume the viscosity of the fluids to be the same. 

If Vo is the volume at 0°, then at t° the expansion formula is Vf = Vo(l + a + + yt ). The table gives values of a, p, and y, and of C, the true coefficient of volume expansion at 20° for some liquids and solutions. The temperature range of the observation is At. Values for the coefficient of volume expansion of liquids can be derived from the tables of specific volumes of the saturated liquid given as a function of temperature later in this section. C = (dV/dt)IVQ... 

If V2 and Vi are the volumes at fa and fi, respectively, then Ua = Vi(l + CAt), C being the coefficient of cubical expansion and Af the temperature interval. Where only a single temperature is stated, C represents the true coefficient of volume expansion at that temperature. 

Account for the fact that the coefficient of volume expansion below Tg is smaller than that above Tg. Why is it said that in the glassy state the polymer is not in a true thermodynamic equilibrium ... 

Relations, first derived by James Clark Maxwell (the Maxwell equations) can be used to express the state functions of entropy and free energy in terms of physically measurable quantities the coefficient of volume expansion (a) and the isothermal compressibility P). 

COEFFICIENT OF VOLUME EXPANSION FOR PETROLEUM WAXES AND PURE N-PARAFFINS. 

Differentiating the equation allows one to obtain the isothermal compressibility, K, and the coefficient of volume expansion, y ... 

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