A change of state where energy is removed from a substance is called an exothermic reaction. This chemical reaction releases energy in the form of light or heat.
The heat energy required to change a substance between solid & liquid at constant temperature is called the "latent heat of fusion". If the change is from solid to liquid the substance gains this energy. If the change is from liquid to solid the substance gives up this energy. The exact amount of latent heat of fusion is different for different substances.
When a substance changes from a liquid to a solid it releases energy. (You take the heat out)
Physical changes are generally easy to reverse because NO ENERGY is produced by the substance.A Chemical change cannot be reversed because ENERGY is produced by the substance forming a new substance.
A substance changes from liquid to gas during evaporation because energy is absorbed. Evaporation is an important part of the water cycle.
When energy is added,solid will melt into liquid or liquid will change into gas. (When energy is added it gains heat).When energy is removed, the liquid will turn into solid or the gas will turn into liquid. (When energy is removed the heat will lose).
When energy is removed from a gas, condensation occurs. When energy is removed from a liquid, freezing occurs.
It's burning.
The energy needed to change a substance from a liquid to a gas is called the enthalpy (or heat) of vaporization.
When thermal energy is removed from a substance, the molecules lose kinetic energy and slow down. This often causes the substance to cool down as the molecules have less energy to move and vibrate. In extreme cases, the substance may undergo a phase change, such as from a liquid to a solid.
The substance's particals will start slowing down and come closer together. As kinetic energy is removed from a substance, it will do the opposite as when kinetic energy is added to a substance.
When heat is transferred in a space the average energy of the particles - the temperature of the substance - is affected, by increasing or decreasing. The change in temperature depends on the number of particles affected.
When energy is added to a substance, the temperature of the substance increases, causing the particles to gain kinetic energy and move faster, resulting in a phase change. Likewise, when energy is removed from a substance, the temperature decreases, causing the particles to slow down and the substance to change phases. The energy absorbed or released during these phase changes is used to either break or form bonds between the particles.
Physical change can occur when energy is added or removed. For example, adding heat energy can cause water to change from a solid to a liquid (melting), while removing heat energy can cause water to change from a liquid to a solid (freezing). These changes do not alter the chemical composition of the substance.
Heat associated with phase change is called Latent Heat
When matter changes state, the molecular energy generally increases as heat is added or decreases as heat is removed. Molecular motion increases as the substance transitions from a solid to a liquid to a gas. The overall mass of the substance remains the same throughout the phase change process, as no particles are added or removed.
Thermal energy of a substance is determined by the movement of the molecules and the potential energy of the arrangement of molecules. Heat transfer will stop when thermal equilibrium is reached. It depends upon the substance how long that takes.
During a change of state, the temperature of a substance remains constant. This is because the energy being added or removed is used to break or form intermolecular bonds rather than increase or decrease the substance's kinetic energy.