Chapter 13 - States Of Matter Flashcards
Kinetic theory
All matter consists of tiny particle that are in constant motion.
Kinetic energy
The energy an object has because of its motion.
What are the assumptions of the kinetic theory as it applies to gasses?
- the particles of a gas are small, hard spheres with insignificant volume.
- the motion of the particles in gas are rapid, constant and random.
- 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.
How does kinetic theory explain gas pressure?
Gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object.
Vacuum
An empty space with no particles and no pressure.
Atmospheric pressure
The collisions of atoms and molecules in air with objects.
Barometer
A device that is used to measure atmospheric pressure.
What is the SI unit of pressure?
Pascal (Pa).
Standard atmosphere (ATM)
1 ATM = 760 mm hg = 101.3 kPa
What is the relationship between the temperature in kelvins and the average kinetic energy of particles?
The kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance.
What factors determine the physical properties of a liquid?
The interplay between the disruptive motions of particles in a liquid and the attractions among the particles determines the physical properties of liquids.
What is the relationship between evaporation and kinetic energy?
During evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid.
Vapor pressure
A measure of the force exerted by a gas above a liquid.
Under what conditions does boiling occur?
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 external pressure on the liquid.
Normal boiling point
The boiling point of a liquid at a normal pressure.
How are the structure and properties of solids related?
The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles.
Melting point
The temperature at which a solid changes into a liquid.
Freezing point
The temperature at which a liquid changes into a solid.
Crystal
The particles are arranged in an orderly, repeating, three dimensional pattern called a crystal lattice.
What determines the shape of a crystal?
The shape of a crystal reflects the arrangements of the particles within the solid.
Unit cell
The smallest group of particles within a crystal that retains the geometric shape of the crystal.
Allotropes
Two or more molecular forms of the same element in the same physical state.
