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 chest pain similar to that produced by costochondritis may include, but are not limited to the following: 1  Cardiac: Heart attack. 2  Gastrointestinal: Gastroesophageal reflux disease. 3  Musculoskeletal: Fibromyalgia. 4  Psychogenic: Anxiety disorder. 5  Respiratory: Pneumonia. 6  Other: Herpes zoster.