What has happened to the nail is a typical example of a chemical change. In a chemical change, a new substance is formed, heat is released and it is not easily reversible.
The nail has undergone chemical change because it no longer conducts heat as it used to. This shows that the chemical composition of the nail has changed.
Also, the change in the physical appearance of the nail from a shinning metal to reddish brown indicates that a chemical change has occurred.
<span>When a chemical reaction occurs and the thermometer in the container records a drop in temperature t</span>he reaction is exothermic because heat was released by the reaction.
<span>B. The reaction is exothermic because heat was released by the reaction. is your answer.
