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Changes of State. Chapter 3, Section 2 Page 96. Section 2: Changes of State. What happens to a substance during changes between solid and liquid? What happens to a substance during changes between liquid and gas? What happens to a substance during changes between solid and gas?.
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Changes of State Chapter 3, Section 2 Page 96
Section 2:Changes of State • What happens to a substance during changes between solid and liquid? • What happens to a substance during changes between liquid and gas? • What happens to a substance during changes between solid and gas?
Changes Between Solid and Liquid The change in state from a solid to a liquid is called melting. The temperature at which a solid melts is its melting point.
Changes Between Solid and Liquid • The change from a liquid to a solid is called freezing. The temperature at which a liquid freezes is its freezing point.
Changes Between Liquid and Gas • The change from a liquid to a gas is called vaporization.
Evaporation • Evaporation is when vaporization takes place only on the surface of a liquid. Water vapor on a lake’s surface.
Boiling • Boiling is when vaporization takes place below its surface as well as at the surface of a liquid. The temperature at which a liquid begins to boil is its boiling point.
Condensation • Condensation is when a gas changes into a liquid. animation Condensation on a bus window
Temperature and Changes of State • A beaker of ice at –10ºC was slowly heated to 110ºC. The graph shows how the temperature of the water changed over time. Animation
Temperature (ºC) on the y-axis, time (minutes) on the x-axis Reading Graphs: What two variables are plotted on the graph? Temperature and Changes of State
The temperature is rising from 0ºC to 100ºC. Reading Graphs: What is happening to the temperature of the water during segment C of the graph? Temperature and Changes of State
Segment B: melting point of ice; segment D: boiling point of water Interpreting Data: What does the temperature value for segment B represent? For segment D? Temperature and Changes of State
Change from solid to liquid; change from liquid to gas Drawing Conclusions: What change of state is occurring during segment B of the graph? During segment D? Temperature and Changes of State
Changes Between Solid and Gas There are times when a solid will change directly into a gas. This process is called sublimation. Snow Dry Ice