What type of energy transfer occurs during combustion?

During combustion, chemical energy stored in the fuel is transformed into thermal energy, which is primarily in the form of heat. This process occurs when a substance (usually a hydrocarbon) reacts with an oxidizer (such as oxygen from the air), leading to an exothermic reaction that releases energy.

The products of combustion, such as gases and heat, are a result of breaking chemical bonds in the fuel and forming new bonds in the combustion products. This transition is fundamental to various applications, such as engines and heating systems, where the heat generated from combustion is harnessed for work or heating purposes.

The other types of energy transfers do not pertain to combustion. Mechanical to electrical energy transfer typically occurs in generators where motion is converted into electricity. Thermal to kinetic energy is common in systems where heat causes movement, such as in heat engines. Electrical to chemical energy transfer is seen in processes like electrolysis but is not relevant to combustion reactions.