Mercury heat capacity

P8.1 The molar enthalpy of vaporization of liquid mercury is 59.229 kJ-mol l at its normal boiling point of 630.0 K. The heat capacities of the liquid and gaseous phases, valid over the temperature range from 250 to 630 K, are as follows ... 

IB The heat absorbed is the product of the amount of mercury, its molar heat capacity, and the temperature change that occurs. 

Low-temperature calorimetry (S83,B112) has been used to study coarse porosity. The method is based on the fact that water in pores freezes at a lower temperature than water in bulk. The ice forms through the advance of a front, analogous to the intrusion of mercury or the desorption of water. Hysteresis effects indicated the existence of necks in the pores, and the occurrence of up to three distinct peaks on curves of apparent heat capacity against temperature was interpreted as indicating maxima in the pore size distribution. Coarsening of the pore structure on drying was confirmed. 

You acquire an insulated 2.000-liter container with a known heat capacity and a built-in electrical heating coil that can deliver a known heat input to the contents of the container. A calibrated thermocouple is used to measure the temperature in the vessel, and the pressure is measured with a mercury manometer. 

Calculate the molar enthalpy change when mercury is cooled 10 K. The molar heat capacity of mercury is 27.8 J/K mol. 

Since is about 6 cal./deg. mole, the difference between the heat capacities is small for solids. For liquids the difference may be quite large, thus for mercury at 630 °C c = 6-72, c = 5 29 cal./deg. mole. 

Since as we have already seen, the heat capacities of solids can be accounted for theoretically, it is of interest to examine whether the heat capacities of liquids can also be predicted in a similar way. We observe in the first place, that in the neighbourhood of the melting point the specific heats of simple solids and liquids are generally nearly equal. J Thus for solid mercury at 234 c = 6 77 cal./deg. mole, while for... 

For certain monatomic gases, such as helium, neon, argon, and mercury and sodium vapors, the ratio of the heat capacities at moderate temperatures has been found to be very close to 1.67, as required by equation (15.6). The values of the individual heat capacities at constant pressure and constant volume are 5.0 and 3.0 cal. deg. mole , respectively, in agreement with equations (15.5) and (15.4). It appears, therefore, that for a number of monatomic gases the energy of the molecules, at least that part which varies with temperature and so affects the heat capacity, is entirely, or almost entirely, translational in character (see, however, 16f). 

The ice calorimeter is an important tool for measuring the heat capacities of liquids and solids, as well as the heats of certain reactions. This simple yet ingenious apparatus is essentially a device for measuring the change in volume due to melting of ice. To measure a heat capacity, a warm sample is placed in the inner compartment, which is surrounded by a mixture of ice and water. The heat withdrawn from the sample as it cools causes some of the ice to melt. Since ice is less dense than water, the volume of water in the insulated chamber decreases. This causes an equivalent volume of mercury to be sucked into the inner reservoir from the outside... 

The heat capacity of liquid mercury at constant pressure is almost constant at 28 J K 1 mol 1 between its freezing point at 234 K and 298 K. Estimate the entropy of liquid mercury at its freezing point. The entropy of liquid mercury at 298 K is 77.4 J K"1 mol"... 

Silver-white, heavy, mobile, liquid metal slightly volatile at ordinary temp solid mercury is a tin-white, ductile, malleable mass which may be cut with a knife, mp —38.87" bp 356.72° dB 13.534, Heat capacity at constant pressure (25 ) 6.687 cal/moie deg. Vapor pressure (25°) 2 X ]0-3 mm heat of vaporization (25 ) 14.652 kcal/mole Busey,... 

The first of these tables gives the molar heat capacity at constant pressure of liquid and gaseous mercury as a function of temperature. To convert to specific heat in units of J/g K, divide these values by 200.59, the atomic weight of mercury. 

The second table gives the molar heat capacity of solid mercury in its rhombohedral (a-mercury) form. 

---