Which of the following is an example of an endothermic reaction?

JAMB Chemistry 2023 63 views

Which of the following is an example of an endothermic reaction?

  1. Burning of methane (CH₄) in the presence of oxygen.
  2. Decomposition of hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen (O₂). ✓
  3. Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl₂).
  4. Combustion of propane (C₃H₈) to produce carbon dioxide (CO₂) and water (H₂O).

Explanation

Hydrogen peroxide decomposition absorbs energy. Endothermic reactions take in heat from surroundings. You need to add energy to break H₂O₂ apart.

Burning methane and propane release heat. Salt formation releases energy. All three are exothermic reactions.

Remember: Endothermic means energy in. Exothermic means energy out.

pastquestions.ng