1. Changes in States of Matter
Created by:
Mrs. Susan Dube

2. Changes in State/Phase changes
A phase describes a physical state of matter that is altered or changed by physical means, thereby creating a physical change!

3. Changing states of matter
Solids can become liquids and liquids can become solids
Liquids can become gases and gases can become liquids
Solids can become gases
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4. Melting – solid to liquid
Melting is the process by which a solid becomes a liquid
Melting point – is the lowest temperature at which a substance begins to melt
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5. Melting and particle arrangement
As solids heat up, the particles gain energy and vibrate faster causing the particles to break loose and slide past one another becoming a liquid (copy into notes)

6. Freezing – liquid to solid
Freezing is the process by which a liquid becomes a solid
Freezing point – is the temperature at which a specific liquid becomes a solid
The substance’s freezing point is the same as the substance’s melting point where the substance could exist either as a solid or a liquid
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7. Freezing and particle arrangement
As a liquid’s temperature is lowered, the particles lose energy and move more slowly.
Eventually, the particles move so slowly that the attraction among them cause the liquid to become a solid (copy into notes)

8. Check for Understanding
What are the ways in which a solid can change state into a liquid or that a liquid can change into a solid? (answer question in notes)

9. Evaporation – liquid to gas
Evaporation is the process by which a liquid becomes a gas
Evaporation usually occurs at the surface of a liquid
The fastest moving particles at the surface of the liquid break away from the liquid and become gas particles
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10. Evaporation and particle arrangement
As the temperature increases, the energy in the liquid increases and the movement of the particles increases allowing them to escape from the liquid and become a gas
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11. Boiling – liquid to gas
Boiling is another process by which a liquid becomes a gas
Boiling point – is the temperature at which the liquid becomes a gas
Substances have specific boiling points
Ex. Water boils at 100⁰C or 212⁰F
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12. Check for understanding
What are the ways in which a liquid changes state into a gas? What happens to the particles during that phase change? (Answer question in notes)

13. Boiling and particle arrangement
As the temperature increases, the energy in the liquid increases and the movement of the particles increases allowing them to escape from the liquid and become a gas
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notes)

14. Sublimation – solid to gas
Sublimation is when a solid changes directly to a gas (Copy into notes)
Ex. Dry ice is frozen carbon dioxide that sublimates

15. Condensation – gas to liquid
Condensation is the process by which a gas becomes a liquid
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16. Condensation and particle arrangement
When you cool a gas, the particles move more slowly and the attraction between the particles increases pulling the particles closer together forming a liquid (copy into notes)

17. Check for understanding
How does sublimation differ from condensation?
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