Skill 11.1e-Explain how chemical energy in fuel is transformed into heat

Skill 11.1e-Explain how chemical energy in fuel is transformed into heat 

The energy in molecules is located in the bonds between the atoms in the molecule (see Competency 1.3). To break these bonds requires energy. Once broken apart, the atoms, ions or molecules rearrange themselves to form new substances, making new bonds. Making new bonds releases energy. 

If during a chemical reaction, more energy is needed to break the reactant bonds than released when product bonds form, the reaction is endothermic and heat is absorbed. The environment becomes colder. 

On the other hand, if more energy is released due to product bonds forming than is needed to break reactant bonds the reaction is exothermic and the excess energy is released to the environment as heat. The temperature of the environment goes up. 

Burning gasoline as a fuel would be a complex example to consider because gasoline is a mixture of hydrocarbons ranging from 5 to 12 carbon atom chains. 

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