Which line BEST describes these changes?

Question

1. Change 1. When calcium carbonate forms calcium oxide and carbon dioxide heat is absorbed.
Change 2. Calcium oxide releases heat when shaken with carbon dioxide.
Which line BEST describes these changes?
1. change 1 is exothermic; change 2 is endothermic
2. change 1 is endothermic; change 2 is endothermic
3. change 1 is exothermic; change 2 is exothermic
4. change 1 is endothermic; change 2 is exothermic

Answer 1

The wording suggests that change 1 is endothermic (heat absorbed) and change 2 is exothermic (heat released), so the correct answer is (4).