1. Created by C. Ippolito June 2007
States of Matter
13.1 The Nature of Gases
13.2 The Nature of Liquids
13.3 The Nature of Solids
13.4 Changes of State
Updated 9/1/2019
Created by C. Ippolito June 2007

2. Created by C. Ippolito June 2007
The Nature of Gases
Objectives
Describe the assumptions of the kinetic theory as it applies to gases
Interpret gas pressure in terms of kinetic theory
Define the relationship between Kelvin temperature and average kinetic energy
Updated 9/1/2019
Created by C. Ippolito June 2007

3. Kinetic Theory & a Model for Gases
Kinetic Energy
energy an object has because of its motion
Kinetic Theory
all matter consists of tiny particles in constant motion
Gas Particles
small, hard spheres of insignificant volume
motion is rapid, constant, and random
collisions are perfectly elastic
Updated 9/1/2019
Created by C. Ippolito June 2007

4. Created by C. Ippolito June 2007
Gas Pressure
result of force exerted by gas per unit surface area of an object
from simultaneous collisions of billions of rapidly moving particles in an object
Vacuum
an empty space with no particles and no pressure
Atmospheric Pressure
from collisions of atoms and molecules in air
Barometer
measures atmospheric pressure
SI unit is the pascal (Pa)
Standard Atmosphere
pressure to support 760mm of Hg at 25°C
1 atm = 760 mm Hg = kPa
Updated 9/1/2019
Created by C. Ippolito June 2007

5. Converting Between Units of Pressure
Updated 9/1/2019
Created by C. Ippolito June 2007

6. Kinetic Energy and Temperature
Average kinetic energy and temperature are related
 kinetic energy  temperature
 kinetic energy  temperature
Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of a substance
Updated 9/1/2019
Created by C. Ippolito June 2007

7. Created by C. Ippolito June 2007
The Nature of Liquids
Objectives
Identify factors that determine physical properties of a liquid
Define evaporation in terms of kinetic energy
Describe equilibrium between a liquid and its vapor.
Identify the conditions at which boiling occurs
Updated 9/1/2019
Created by C. Ippolito June 2007

8. Created by C. Ippolito June 2007
Model for Liquid
Intermolecular forces of attraction keep liquid particles close together
interplay between disruptive particles in a liquid and the attraction of particles determine the physical properties of liquids
Liquid particles are
closer together than gases
more dense than gases
little affected by pressure
Updated 9/1/2019
Created by C. Ippolito June 2007

9. Created by C. Ippolito June 2007
Evaporation
Vaporization
conversion of a liquid into a gas
Evaporation
process by particles at surface of liquid converts to gas without boiling
only molecules with a certain minimum kinetic energy can escape from surface of liquid
Updated 9/1/2019
Created by C. Ippolito June 2007

10. Created by C. Ippolito June 2007
Vapor Pressure
measure of the force exerted by a gas above a liquid
at constant vapor pressure, a dynamic equilibrium exists between the vapor and liquid.
rate of evaporation = rate of condensation
 temperature  vapor pressure
Updated 9/1/2019
Created by C. Ippolito June 2007

11. Vapor Pressure Measurement
Manometer
measures vapor pressure
Updated 9/1/2019
Created by C. Ippolito June 2007

12. Created by C. Ippolito June 2007
Boiling Point
A liquid begins to boil, when heated to a temperature at which all of its particles have enough kinetic energy to vaporize
Boiling Point
temperature where
vapor pressure of liquid = external pressure on liquid
Updated 9/1/2019
Created by C. Ippolito June 2007

13. Boiling Point and Pressure Changes
Updated 9/1/2019
Created by C. Ippolito June 2007

14. Created by C. Ippolito June 2007
Normal Boiling Point
boiling point at 1 atm or kPa
Updated 9/1/2019
Created by C. Ippolito June 2007

15. Created by C. Ippolito June 2007
The Nature of Solids
Objectives
Evaluate how the way particles are organized explains the properties of solids
Identify the factors that determine the shape of a crystal
Explain how allotropes of an element are different
Updated 9/1/2019
Created by C. Ippolito June 2007

16. Created by C. Ippolito June 2007
Model for Solids
General properties of solids reflect an orderly arrangement of particles and the fixed location of particles
Melting Point
temperature at which a solid changes into a liquid
Updated 9/1/2019
Created by C. Ippolito June 2007

17. Crystal Structure & Unit Cells
shape of a crystal reflects the arrangement of the particles
Crystal Systems
Seven Systems
Cubic, Tetragonal, Orthorhombic, Monoclinic, Triclinic, Hexagonal, Rhombohedral
characterized in terms of
angles between faces (α, β, γ)
length of edges on each face (a, b, c)
Unit Cell
smallest group of particles that retain geometric shape of the crystal
Simple Cubic
Body Centered
Face Centered
Updated 9/1/2019
Created by C. Ippolito June 2007

18. Created by C. Ippolito June 2007
Allotropes
two or more different molecular forms of the same element in the same physical state
different properties
different structures
Carbon (diamond, graphite, fullerenes)
Updated 9/1/2019
Created by C. Ippolito June 2007

19. Created by C. Ippolito June 2007
Changes of State
Objectives
Identify the conditions necessary for sublimation
Describe how equilibrium conditions are represented in a phase diagram
Updated 9/1/2019
Created by C. Ippolito June 2007

20. Created by C. Ippolito June 2007
Sublimation
change of a substance from a solid to a vapor without passing through the liquid state
occurs in solids with vapor pressures that exceed atmospheric temperature at or near room temperature
Updated 9/1/2019
Created by C. Ippolito June 2007

21. Created by C. Ippolito June 2007
Phase Diagrams
A graphic representation of the relationships among solid, liquid, and vapor states in a sealed container
pressure and temperature at which two phases exist in equilibrium are indicated by a line separating the phases
triple point
the only set of conditions at which all three phases can exist at equilibrium
Updated 9/1/2019
Created by C. Ippolito June 2007