Dulong and Petit's Law: We Should Not Ignore Its Importance

Abstract

Dulong and Petit's law played an important role in the development of the periodic table as Mendeleyeff used this method in 1870 to correct the atomic weights of indium, cerium, and uranium that were wrong in the table of 1869. The discontinuous variation of molar heat capacity of a solid with change in temperature can be due to a phase change, order–disorder phenomena, or magnetic transitions. Two student exercises are described: the determination of the specific heat of a metal and hence its atomic weight (lab experiment) and a graphical study of specific heat versus atomic weight for different groups of metals and the confirmation of Dulong and Petit's law (classroom activity). The molar heat capacity is shown to be close to 26 J mol-1 K-1 for the solid elements. The anomalously low values for Be, B, C, and Si are explained by the Debye theory. The large value for Gd is shown to be a result of its magnetic properties; its Curie temperature is close to room temperature. The exercises are suitable for the general chemistry course.

Band Engineering for Realizing Large Effective Mass in Cu3SbSe4 by Sn/La Codoping

“…The carrier concentration ( n H ) and mobility ( μ H ) were performed by the Hall effect measurement system (HMS-3000, ECOPIA) on the sanded samples (thickness about 500 μm) in constant magnetic fields of up to ±0.525 T. The thermal diffusivity ( D ) of our pellet samples (diameter of ∼12.7 mm and thickness of ∼1.8 mm) was obtained by using a laser flash method (XFA 1000, Linseis). κ tot could be obtained by using κ tot = DC p d where d is the density of the sintered samples; all the specific heat capacity ( C p ) were used with the theoretical value ( C p ≈ 0.318 Jg –1 K –1 , which is calculated by the Dulong–Petit formula , ).…”

The field theory of specific heat

“…A.T. Petit and P.L. Dulong measured how fast solid bodies cooled down in low pressure air and found that the specific heat capacities of the bodies were inversely proportional to the atomic weights of the bodies' chemical elements [1,24]. Therefore, the Dulong-Petit law states that the product of the molar mass, M , with the specific heat, C V , of mono-atomic solid bodies, i.e., the molar specific heat,…”

“…The Dulong-Petit law was important not only in physics, but also in chemistry, where it helped Dmitry Mendeleev to discover the periodic table of chemical elements [24]. Mendeleev used the Dulong-Petit law to correct wrong atomic weights of three elements (cesium, uranium and indium) by making new measurements of their specific heats.…”

Additive-assisted synthesis and optoelectronic properties of (CH3NH3)4Bi6I22

“…Interestingly, a similar behavior has been observed for systems containing light atoms that are strongly bonded to each other, causing some vibrational modes to be unpopulated even at 300 K due to their high vibrational frequencies. 54 This indicates the presence of complex vibrational behavior in this material with strong anharmonicity, 55 which should be studied further by other techniques such as inelastic neutron scattering. In general , beyond structural phase transitions, thermochromism can also be induced by subtle changes to the bond distances and angles in metal halides such as in the case of the related iodobismuthates featuring isolated…”