KAMSC Honors Biology Semester 1 Practice Exam 2026 – The Complete Guide to Mastering Your Biology Exam!

When a log is burning, the high-energy bonds within the organic molecules of the wood (primarily cellulose and lignin) undergo chemical reactions during combustion. These high-energy bonds are broken as the wood is exposed to heat and oxygen. The breaking of these bonds releases energy in the form of heat and light, which is characteristic of fire.

As these high-energy bonds break, they allow for the formation of new, lower-energy bonds in the products of combustion, such as carbon dioxide and water. This transformation is a key aspect of energy conversion during combustion, where stored chemical energy is released into the surrounding atmosphere.

The process also results in the logs being reduced to ashes as a byproduct, but it is the breaking of the chemical bonds and the subsequent formation of new molecules that dictates the energy transformation happening in the burning log. Thus, the statement about the formation of new low-energy bonds accurately describes the underlying chemistry involved in the burning process.