Question

A student mixes two chemicals in a test tube. She notices that the mixture starts to bubble and the test

tube feels very warm. The student most likely concludes that the mixture is-
F. a chemical reaction that happened too quickly.
G. an endothermic reaction that absorbed thermal energy.
H. an exothermic reaction that released thermal energy.
J. not a chemical reaction.

Answer 1

H. an exothermic reaction that released thermal energy.

Step-by-step explanation:

The student will most conclude that this is a chemical reaction in which thermal energy is released to the environment.

Such reactions accompanied by the release of thermal energy are exothermic reactions.

• In an exothermic change, heat is liberated to the surrounding.
• The surrounding becomes hotter at the end of the changes.
• For such reaction we say that enthalpy change is negative.

For endothermic reactions, heat is absorbed. At the end of the reaction, the system is cold.