Chapter 10: States of Matter
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Chapter 10: States of Matter
What is the kinetic-molecular theory?
a theory based on the idea that particles of matter are always in motion
What is an ideal gas?
An ideal gas is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory
What are the five assumptions for the kinetic-molecular theory of gases?
1. Gases consist of large numbers of tiny particles that are for apart relative to their size
2. Collisions between gas particles and between particles and container walls are elastivc collisons
3. Gas particles are in continuous, rapid, random motion (possess kinetic energy, which is energy of motion)
4.There are no forces of attraction between gas particles
5. The temperature of a gas depends on the average kinetic energy of the particles of the gas
What is the formula for kinetic energy? What does each variable stand for?
m - the mass of the particle
v - the speed
What are the ways in which the kinetic-molecular theory accounts for the physical properties of the gas?
Expansion, Fluidity, Law Density, Compressibility, Diffusion/Effusion
What is a fluid?
liquids or gases that flow
Differentiate between diffusion and effusion
Diffusion is a process by which particles of a gas spread out spontaneously and mix with other gases. In contrast, effusion is a process by which gas particles pass through a tiny opening
What is a real gas?
A gas that does not behave completely according to the assumption of the kinetic-molecular theory
Which is the least common state of matter?
What is a liquid?
A form of matter that has a definite volume and takes the shape of its container
Explain the particles in a liquid
Particles in a liquid are in constant motion, and closer together than in a gas
What is a fluid?
A substance that can flow and therefore take the shape of its container
What are the five properties of a liquid?
Relatively High Density, Relative Incompressibility, Ability to Diffuse, Surface Tension, Evaporation and Boiling
What is surface tension?
A force that tends to pull adjacent parts if a liquid's surface together, there by decreases surface area to the smallest possible size
What is capillary action?
the attraction of the surface if a liquid to the surface of a solid
How are vaporization and evaporation connected?
Evaporation is a form of vaporization
the process by which a liquid or solid changes to a gas
the process by which particles escape from the surface of a non-boiling liquid and enter the gas phase
What is freezing?
The physical change of a liquid to a solid by removal of energy as heat (solidification)
What are the interparticle attractions that exert stronger effects in solids vs. liquids and gases?
dipole-dipole attracts, London dispersion forces, and hydrogen bonding exert stronger effects in solids than in liquids or gases
What are the two types of solids?
crystalline and amorphous
consist of crystals
one in which the particles are arranged randomly
What are the four properties of a solid?
Definite Shape and Volume, Definite Melting Point, High Density/Incompressibility, Low Rate of Diffusion
What is melting? Melting point?
is the physical change of a solid to liquid by the addition of energy as heat. The temperature at which a solid becomes a liquid is its
What is a supercooled liquid?
substances that retain certain liquid properties even at temperatures at which they appear to be solid
What is a crystal structure?
the total three-dimensional arrangement of particles of a crystal
What is a unit cell?
the smallest portion of a crystal lattice that shows the 3rd pattern of the entire lattice
What are four types of crystals?
1. ionic crystals
2. covalent network crystals
3. metallic crystals
4.covalent molecular crystals
What is an amorphous solid? Give an example.
Particles are arranged randomly (glasses, plastics, etc.)
What is a phase?
any part of a system that has uniform composition and properties
List and briefly define the six phase changes of matter
solid to liquid (melting)
solid to gas (sublimation)
liquid to solid (freezing)
liquid to gas (vaporization)
gas to liquid (condensation)
gas to solid (deposition)
What is the equilibrium vapor pressure of a liquid?
the pressure exerted by a vapor in equilibrium with its corresponding liquid of a given temperature
What is a volatile lquid? What kind of attractive forces do the particles have? Give an example.
A liquid that evaporates readily. Attractive forces are relatively weak.
What is the boiling point? What affects it?
the temperature at which the equilibirum vapor pressure of the liquid equals the atmospheric pressure
What is the molar enthalpy of vaporization? What is the magnitude of it?
The amount of energy as heat that is needed to vaporize one mole of liquid at the liquid's boiling point at constant pressure.
What is the freezing point?
the temperature at which the solid and liquid are in eqrruilibrium at 1 atm (760 torr, or 101.3 Ba) pressure
What is a phase diagram? What does it reveal?
A graph of pressure versus temperature that shows the conditions under which the phases of a substance exist (reveals how the states of a system change with changing temperature.
of a substance indicates the temperature and pressure conditions at which the solid, liquid, and vapor of the substanc ecan coexist at equilibrium
of a substance indicates the critical temperature and critical pressure
is the temperature above which the substance cannot exist in the liquid state
What percentage of the Earth is water?
What percentage of living things is water?
70% to 90%
What type of bond is involved in water
polar covalent bonds, hydrogen-hydrogen bonds
What happens to the volume when water feezes?
it expands in volume as it freezes becayse its molecules form an open rigid structure
What is the molar enthalpy of fusion and of vaporization?
Under a pressure of 1 atm (101.3 kPa), water boils at 100 degrees Celsius. At this temperature, water's molar enthalpy of vaporization is 40.79 k7/mol