Which statement best describes how chemical reactions involve energy?

• A. Chemical reactions always absorb energy from their surroundings.
• B. Chemical reactions do not affect the energy of the system.
• C. Chemical reactions involve the breaking and forming of bonds, which can either release or absorb energy.
• D. Chemical reactions only release energy in the form of heat.

Answer: (C)

Verified step by step guidance

1. Understand that chemical reactions involve changes in the arrangement of atoms, which means bonds are broken and new bonds are formed.
2. Recognize that breaking chemical bonds requires energy input (endothermic process), while forming new bonds releases energy (exothermic process).
3. Realize that the overall energy change of a reaction depends on the balance between the energy absorbed to break bonds and the energy released when new bonds form.
4. Know that chemical reactions can either absorb energy from the surroundings or release energy to the surroundings, depending on the specific reaction.
5. Conclude that the best description is that chemical reactions involve both breaking and forming bonds, which can either release or absorb energy.