1. States and state change
Chapter 11 sec 1
States and state change

2. States of Matter
The fundamental difference between states of matter is the distance between particles.

3. States of Matter
Gases – fill container, random rapid motion, never coming to rest or clumping together
Motion is mainly translational
Liquids – fixed volume, flow and assume shape of container, only slightly compressible, stronger forces hold molecules together
Motion is mainly translational
EOS
Solids – fixed volume, definite shape, generally less compressible than liquids, forces hold particles in a fixed shape
Motion is mainly vibrational

4. Solid particles have fixed position
Crystalline form: they can be very hard and brittle or they can be very soft.

5. Liquid particles can move easily past one another
Liquid flow to take the shape of the lower part of a container.
A meniscus is the interface between a liquid and the air above it
EOS
Capillary action results from intermolecular interactions

6. Surface Tension
Surface tension (g) is the amount of work required to extend a liquid surface and is usually expressed in unit of J m–2
Adhesive forces are intermolecular forces between unlike molecules
Cohesive forces are intermolecular forces between like molecules
EOS

7. Vaporization and Condensation
Vaporization is the conversion
of a liquid to a gas.
EOS
Condensation is the change of a gas to a liquid.
The boiling point of a liquid is the temperature at which its vapor pressure becomes equal to the external pressure

8. Phase Changes Involving Solids
The conversion of a solid to a liquid is called melting, or fusion, and the temperature at which a solid melts is its melting point
Sublimation is the process of a molecule’s passing directly from the solid to the vapor state

9. Phase Diagrams
A phase diagram is a graphical representation of the temperature and pressure conditions under which a substance exists as a solid, liquid, gas, or some combination of these in equilibrium
EOS
critical point
fusion curve
vapor pressure curve
sublimation curve
triple point

10. Practice
A sample of water has a fixed volume and shape. What state is it in?
What property of a liquid enable you to pour a liquid into a cup until the top of the liquid is slightly higher than the top of the cup?
During what process does a liquid change to solid?
solid
Surface tension
freezing