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.

H. an exothermic reaction that released thermal energy.

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.

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

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.