1. Possible Changes of State
Section 4 Changes of State
Chapter 10
Possible Changes of State

2. Mercury in Three States
Section 4 Changes of State
Chapter 10
Mercury in Three States

3. Changes of State and Equilibrium
Section 4 Changes of State
Chapter 10
Changes of State and Equilibrium
Phase - any part of a system that has uniform composition and properties.
Condensation - process by which a gas changes to a liquid.
Vapor - gas in contact with its liquid or solid phase.
Equilibrium - dynamic condition in which two opposing changes occur at equal rates in a closed system.

4. Liquid-Vapor Equilibrium System
Section 4 Changes of State
Chapter 10
Liquid-Vapor Equilibrium System

5. Equilibrium Vapor Pressure of a Liquid
Section 4 Changes of State
Chapter 10
Equilibrium Vapor Pressure of a Liquid
Equilibrium vapor pressure - pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature
The equilibrium vapor pressure increases with increasing temperature.
Increasing the temperature of a liquid increases the average kinetic energy of the liquid’s molecules.

6. Measuring the Vapor Pressure of a Liquid
Section 4 Changes of State
Chapter 10
Measuring the Vapor Pressure of a Liquid

7. Equilibrium Vapor Pressure of a Liquid
Section 4 Changes of State
Chapter 10
Equilibrium Vapor Pressure of a Liquid
Volatile liquids - liquids that evaporate readily.
They have relatively weak forces of attraction between their particles.
example: ether

8. Section 4 Changes of State
Chapter 10
Boiling - conversion of a liquid to a vapor within the liquid as well as at its surface.
Boiling point - temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure.
The lower the atmospheric pressure is, the lower the boiling point is.

9. Chapter 10 Boiling The normal boiling point of water is exactly 100°C.
Section 4 Changes of State
Chapter 10
Boiling
The normal boiling point of water is exactly 100°C.

10. Section 4 Changes of State
Chapter 10
Molar enthalpy of vaporization (∆Hv) - amount of energy as heat that is needed to vaporize one mole of liquid at the liquid’s boiling point at constant pressure
Molar enthalpy of fusion (∆Hf) - amount of energy as heat required to melt one mole of solid at the solid’s melting point

11. Section 4 Changes of State
Chapter 10
Sublimation - change of state from a solid directly to a gas
Deposition - change of state from a gas directly to a solid

12. Comparing Sublimation and Deposition
Visual Concepts
Chapter 10
Comparing Sublimation and Deposition
Click below to watch the Visual Concept.
Visual Concept

13. Chapter 10 Phase Diagrams
Section 4 Changes of State
Chapter 10
Phase Diagrams
Phase diagram - graph of pressure versus temperature that shows the conditions under which the phases of a substance exist.
Triple point - indicates the temperature and pressure conditions at which the solid, liquid, and vapor of the substance can coexist at equilibrium.
Critical point - indicates the critical temperature and critical pressure.

14. Section 4 Changes of State
Chapter 10
Critical temperature (tc) - temperature above which the substance cannot exist in the liquid state.
Above this temperature, water cannot be liquefied, no matter how much pressure is applied.
Critical pressure (Pc ) - lowest pressure at which the substance can exist as a liquid at the critical temperature.

15. Chapter 10 Phase Diagram Visual Concepts
Click below to watch the Visual Concept.
Visual Concept

16. Phase Diagram for Water
Section 4 Changes of State
Chapter 10
Phase Diagram for Water

17. Section 4 Changes of State
Chapter 10
Phase Diagram for CO2

18. Section 4 Changes of State
Chapter 10
Changes of State