nonpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.2  Twitter.onpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.
When is a barrel chest a sign of a disease process? Chronic obstructive pulmonary disease (COPD) is the most common instance in which a barrel chest will occur. In these cases, itâs a sign of the lungs being over-expanded. This is caused by the loss of elasticity and results in the person having hyper-inflated lungs.
Other causes of COPD are: 1  Prolonged exposure to air pollution, such as that seen with burning coal or wood and with industrial air pollutants.  Infectious diseases: Infectious diseases that destroy lung tissue in patients with hyperactive airways or asthma also may contribute to causing this COPD.