Question

which best describes how combustion works?
○ it breaks and forms bonds of fuel to release thermal energy.
○ it breaks and forms bonds of fuel to release chemical energy.
○ it breaks and forms bonds of coolant to release thermal energy.
○ it breaks and forms bonds of coolant to release chemical energy.

Explanation:

Combustion is a chemical reaction where fuel (like hydrocarbons) reacts with oxygen. In this process, bonds in the fuel are broken and new bonds are formed (with oxygen, forming products like CO₂ and H₂O). This reaction releases thermal energy (heat). Coolant is used to absorb heat, not involved in combustion as a reactant. Chemical energy in fuel is converted to thermal energy during combustion. So the correct option is the one about fuel and releasing thermal energy.

Answer:

A. It breaks and forms bonds of fuel to release thermal energy.