Humber Admissions Practice Test

What is external energy in the context of chemical reactions?

1. Energy from within the object

2. Energy applied to an object by another source

3. Energy released during a reaction

4. Energy stored in chemical bonds

The correct answer is: Energy applied to an object by another source

External energy in the context of chemical reactions refers to energy that is applied to an object by another source. This can include heat, light, or electrical energy that is provided from an outside source to initiate or drive a chemical reaction. For instance, when you heat a substance to increase the rate of a reaction or when you use electricity in electrolysis, you are applying external energy. This concept is essential because many chemical reactions do not occur spontaneously under standard conditions and require an external energy input to proceed. The other options represent different types of energy relevant to chemical processes but do not correctly define external energy. Energy from within the object refers to internal energy, while energy released during a reaction pertains to products of the reaction rather than energy input. Similarly, energy stored in chemical bonds relates to the inherent energy within the reactants and products, rather than the external energy required to facilitate a reaction.