Chapter 13 - hitmanscience.weebly.com€¦ · Chapter 13 States of Matter. 13.1 The Nature of...
Transcript of Chapter 13 - hitmanscience.weebly.com€¦ · Chapter 13 States of Matter. 13.1 The Nature of...
Chapter 13States of Matter
13.1 The Nature of Gases
Kinetic: motion
Kinetic energy: energy in motion
Kinetic Theory: All matter consists of tiny particles that are in constant motion.
3 Kinetic Laws:
1) The particles in a gas are considered to be small, hard spheres with an insignificant volume.
2) The motion of the particles in a gas is rapid, constant and random.
3) All collisions between particles in a gas are perfectly elastic.
Gas Pressure: results from the force exerted by a gas per unit surface area of an object.
● Gas pressure is the result of simultaneous collisions of billions of rapidly moving particles in a gas with an object.
● Vacuum: An empty space with no pressure and no particles.
Atmospheric Pressure: results from the collisions of atoms and molecules in air with objects.
Barometer: Measures the amount of atmospheric pressure. (mmHg)
Pascal (Pa): SI unit of pressure
Standard Atmosphere (atm): pressure required to support 760 mmHg at 25 degree celcius.
1 atm = 760 mmHg = 101.3kPa
● Conversion methods stay the same!!!
● The amount of Kinetic energy varies based on the different substances.
Kelvin Temperature: directly proportional to the average kinetic energy of the particles of the substance.
13.2 - The Nature of Liquids
● The way particles interact within a liquid determine the physical properties of the liquid.
Vaporization: Liquid to gas
Evaporation: When vaporization occurs at the surface of a liquid when it is not boiling.
● During evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid.
Vapor Pressure: measure of the force exerted by a gas above a liquid.
● Over time, the number of particles entering the vapor increases and some of the particles condense and return to the liquid.
● When a liquid is heated to a temperature at which particles throughout the liquid have enough kinetic energy to vaporize, the liquid begins to boil.
Boiling Point: The temperature at which the vapor pressure of the liquid is just equal to the external pressure on the liquid.
Altitude and boiling point: Water boils at lower temperatures when placed at higher altitudes.
Example: Water boils at 212 degrees fahrenheit in Sonoma, Ca.
Water boils at 202 degrees fahrenheit in Denver, Co.
Normal Boiling Point: boiling point of a liquid at a pressure of 101.3kPa.
13.3 - The Nature of Solids
● The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles.
Melting Point: is the temperature at which a solid changes into a liquid.
Crystal: particles are arranged in an orderly, repeating, 3-D pattern called a CRYSTAL LATTICE.
Allotropes: 2 or more different forms of the same element in the physical state.
- Carbon, phosphorus, sulfur, oxygen (O2 and O3), Boron, and Antimony.
Amorphous Solid: lacks an ordered internal structure.
- Rubber, plastic and asphalt
Glass: a transparent fusion product of inorganic substances that have cooled to a rigid state without crystallizing.
13.4 - Changes of State
Sublimation: The 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 pressure at or near room temperature.
Phase Diagrams: Graph representation of the relationship among solid, liquid and vapor states (or phases) of a substance in a sealed container.
● The conditions of pressure and temperature at which two phases exist at equilibrium are indicated on a phase diagram by a line separating the phases.
Triple Point: describes the only set of conditions at which all three phases can exist in equilibrium with one another.
● For water, the triple point is a temperature of .016 degree Celsius and a pressure of .61 kPa (.0060 atm).