Chemistry

Nearly always, but there are compounds which formed endothermically, so their decomposition gives out energy.

Both conduction and convection. Conduction involves the small movements of individual particles, convection can be on a much larger scale with a hot liquid or gas rising and a cool liquid or gas dropping.

Exothermic Reaction

expand and grow frow larger

All reactions require an activation energy. Some appear not to because that energy is provided enough by their temperature. Thus, there is no reaction that does not require any initial energy to occur.

A reaction that results in an overall release of energy is called an exothermic reaction.

balanced equation

The number in front of a chemical formula is called a coefficient.

false

False,Only coefficients can be changed in order to balance a chemical equation. Subscripts are part of the chemical formula for reactants or products and cannot be changed to balance an equation.

the melted rock called magma is less dense than a solid rock