Chemical reactions that release energy will not occur without a source of energy. So the answer is release.
Answer:
it can last for 30 minutes
Explanation:
because it is very good at giving off heat, extothermal heat can last for quite a while.
Explanation:
For example, Identify the number and type of ions formed in a reaction of calcium and carbon. Step 1: Determine the number of valence electrons for each element and whether the element loses or gains electrons. Calcium has 2 valence electrons and is a metal so it will give up two electrons.