Download presentation
Presentation is loading. Please wait.
Published byGilbert Buck Woods Modified over 9 years ago
2
A change of state is the conversion of a substance from one state to another All changes of state are physical changes The identity of a substance does not change
3
During a change of state, the energy of a substance changes The energy of a substance is related to the motion of its particles If energy is added to a substance, its particles move faster If energy is removed from a substance, its particles move slower
4
The temperature of a substance is a measure of the speed of its particles This means temperature is a measure of the energy of a substance A transfer of energy, known as heat, causes the temperature of a substance to change and can lead to a change of state
5
Melting is the change of state fro a solid to a liquid The melting point of a substance is the temperature at which the substance changes fro a soli to a liquid Most substances have a unique melting point that can be used with other data to identify them Melting point is a characteristic property of a substance
6
For a solid to melt, particles must overcome some of their attraction to each other When a solid is at its melting point, any energy it absorbs increases the motion of its atoms or molecules Melting is an endothermic change because energy is absorbed
7
Freezing is the change of state from a liquid to a solid The temperature at which a liquid changes from a liquid to a solid is it freezing point Freezing and melting occur at the same temperature Freezing is an exothermic change because energy is removed from the substance
8
Vaporization is the change of state from a liquid to a gas Boiling is vaporization that occurs throughout a substance The temperature at which a substance boils is called its boiling point Boiling point is a characteristic property of a substance
9
Evaporation is vaporization that occurs at the surface of a liquid below its boiling point When you perspire, your body is cooled by the process of evaporation Evaporation also explains why water in a glass on a table will disappear after a few days
10
Condensation is the change of state from a gas to a liquid The condensation point of a substance is the temperature at which the gas becomes a liquid and is the same temperature as the boiling point at a given pressure Condensation is an exothermic change
11
Sublimation is the change of state from a solid directly into a gas Frozen carbon dioxide (dry ice) will change from a solid directly to a gas The molecules must go from being very tightly packed to being very spread apart Sublimation is an endothermic change
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.