SSC MTS EXAM

Detailed explanation-1: -If heat is added to a substance, such as in melting, vaporization, and sublimation, the process is endothermic. In this instance, heat is increasing the speed of the molecules causing them move faster (examples: solid to liquid; liquid to gas; solid to gas).

Detailed explanation-2: -Freezing: the substance changes from a liquid to a solid. Melting: the substance changes back from the solid to the liquid. Condensation: the substance changes from a gas to a liquid. Vaporization: the substance changes from a liquid to a gas.

Detailed explanation-3: -A phase change is when matter changes to from one state (solid, liquid, gas, plasma) to another. (see figure 1). These changes occur when sufficient energy is supplied to the system (or a sufficient amount is lost), and also occur when the pressure on the system is changed.