TeXes Science Practice Test

Which characteristics make covalent compounds poor conductors of heat?

1. Large molecular size only

2. I and III only

3. I and II only

4. II and III only

The correct answer is: I and II only

Covalent compounds are generally poor conductors of heat due to their molecular structure and bonding characteristics. This is largely influenced by the nature of covalent bonds, which involve the sharing of electrons between atoms. One contributing factor is the bond type itself. Covalent bonds lack the free-moving charged particles that are essential for efficient thermal conduction. Unlike metals, which have a sea of delocalized electrons that can move freely and transfer energy rapidly, covalent compounds consist of discrete molecules or molecular structures that do not facilitate the movement of thermal energy in the same way. Another aspect to consider is the relatively large molecular size of many covalent compounds. Larger molecules can hinder the vibrational energy transfer necessary for heat conduction. In these larger structures, the energy may not effectively propagate through the entire molecule due to localized vibrations that do not efficiently transfer energy to adjacent molecules. Therefore, while the size and bonding characteristics of covalent compounds play significant roles, the combination of both these factors contributes to their overall poor thermal conductivity.