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.
Causes of COPD. Chronic obstructive pulmonary disease (COPD) occurs when the lungs and airways become damaged and inflamed. It's usually associated with long-term exposure to harmful substances such as cigarette smoke. Things that can increase your risk of developing COPD are outlined below.