Similar presentations

States of Matter

Kinetic Energy Energy due to the motion of an object. –It includes the vibrations and movement within and between the particles.

In science, temperature refers to the kinetic energy of an object,

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 11 Kinetic Molecular Theory Postulates A gas consists of a collection of small particles traveling in straight- line motion and obeying Newton's Laws.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 15 Postulates The average kinetic energy of a molecule is 3/2 kT T is the absolute temperature. k is a constant

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 21 The more gas molecules there are, the more often the walls of the container are hit, therefore the Gas Pressure is higher..

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 22 If the temperature (energy) of the gas is increased the molecules move faster and so hit the walls harder causing the Gas Pressure to rise also.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 29 Atmospheric Pressure Pressure of the Air molecules hitting the earth. (or any other surface in the atmosphere). 14 lbs. per square inch

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 32 Atmospheric Pressure = Weight of the Air Results from the mass of the air being pulled toward the center of the earth by GRAVITY. Measures using a barometer.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 33 Figure 5.2 A Torricellian Barometer At sea level = 760 mm Hg At elevation of 9600 feet = 520 mm Hg

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 34 Pressure 4 is equal to force/unit area 4 SI units = Newton/meter 2 = 1 Pascal (Pa) 4 1 standard atmosphere = 101,325 Pa 4 1 standard atmosphere = 1 atm = 760 mm Hg = 760 torr

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 35 Pressure Units 1 atmosphere (atm) = 760 mm Hg = 760 torr = 101,325 Pa = 29.92 inch Hg = 14.7 lb/ in 2 (psi)

Particles attracted to each other, but more easily separate

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 39 Some Properties of a Liquid Surface Tension: The resistance to an increase in its surface area (polar molecules). Capillary Action: Spontaneous rising of a liquid in a narrow tube. Viscosity: Resistance to flow (molecules with large intermolecular forces).

How does a liquid turn into a gas? It needs enough kinetic energy!!! Called Vaporization 2 ways to vaporize: –1. evaporation- occurs at the surface of a liquid –2. boiling- occurs throughout the liquid.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 43 Liquids Vapor Pressure: Measure of the force exerted by a gas above a liquid. Increasing Temperature increases vapor pressure.

Some molecules will condense back into a liquid. A dynamic equilibrium exists between the vapor and the liquid.

Vapor pressure increases with Temperature. 13. 2

Boiling Point A liquid boils when its vapor pressure is equal to the external pressure.

The normal boiling point is the boiling point of a liquid at atmospheric pressure (1 atm or 101.3 kPa)

Solids Most solids have a special type of pattern that the molecules arrange in.

Solid Water – ICE!

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 52 Types of Solids Crystalline Solids: highly regular arrangement of their components Amorphous solids: considerable disorder in their structures (glass).

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 55 Crystalline Solid Unit Cell: The smallest repeating unit of the lattice. Three common types: 4 simple cubic 4 body-centered cubic 4 face-centered cubic

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 58 Allotropes Two or more different forms of the same element in the same physical state. Allotropes of carbon: diamond, graphite and buckminsterfullerene

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 64 CHANGES OF STATE (PHASE TRANSISTIONS) 1) MELTING: s l 2) FREEZING: l s 3) VAPORIZATION: l g 4) SUBLIMATION: s g 5)CONDENSATION: LIQUEFACTION: g l DEPOSITION: g s

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 65 PHASE DIAGRAMS GRAPHICAL WAY TO SUMMARIZE THE PHASES OF A SUBSTANCE AS A FUNCTION OF TEMPERATURE ANE PRESSURE DIAGRAMS NOT DRAWN TO SCALE