Honors Chemistry Chapter 10: States of Matter

Properties/abilities of solids

1- DEFINITE SHAPE & VOLUME 2- DEFINITE MELTING POINT melting is the physical change from a solid to a liquid by the addition of heat melting point is the temperature at which a solid becomes a liquid supercooled liquid is a substance that retains certain properties of a liquid even at temperatures where it appears to be a solid (glass, plastics,...) 3- HIGH DENSITY (10x a liquid & 10,000x a gas) 4- INCOMPRESSIBILITY 5- LOW RATE OF DIFFUSION

Kinetic-molecular theory of Gases

1- Gases consist of large numbers of tiny particles that are far apart relative to their size. 2- Collisions between gas particles and between particles and their container walls are elastic. An elastic collision is one in which there is no net loss of total kinetic energy. 3- Gas particles are in continuous, rapid, random motion. They therefore possess kinetic energy (energy in motion). 4- There are no forces of attraction between gas particles. 5- The temperature of a gas depends upon the average kinetic energy of the particles of the gas.

Kinetic-molecular theory of liquid

1- Liquids have a high density relative to gases. Their density is about 1000 x that of the gas of the same substance. 2- Liquids are relatively not compressible. 3- Liquids have the ability to diffuse. 4- Liquids exhibit surface tension, a force that tends to pull adjacent parts of a liquid's surface together, thereby decreasing the surface area to its smallest possible size. Surface tension resists penetration of objects into a liquid. 5- Liquids have capillary action, the attraction of the surface of a liquid to the surface of a solid.

What is a liquid?

A LIQUID is a substance that has definite volume but indefinite shape (it takes the shape of its container).

What is a phase diagram?

A phase diagram is a graph of pressure versus temperature that shows the conditions under which the phases of a substance exist.

Effusion

A process by which gas particles under pressure pass through a tiny opening from one container to another.

Gases are (incompressible/compressible)?

COMPRESSIBLE- Gases can be compressed (the volume decreases) by applying pressure to the gas.

deposition

Deposition is the process by which a gas changes directly to a solid, bypassing the liquid state. An example would be frost

why does ice float on water?

Due to the crystal structure of ice, it is less dense than liquid water and will float

freezing

Freezing is the physical change of a liquid becoming a solid. Also called solidification or fusion.

What is freezing point?

Freezing point is the temperature at which a liquid becomes a solid and the solid and the liquid are at equilibrium.

Expansion

Gases do not have definite shape or volume. They expand to completely fill any container.

Fluidity

Gases flow so they are fluids

Diffusion

Gases have the ability to spread and mix with one another due to the random motion of their particles.

How is glass made?

Glass is made by cooling molten materials in a way that prevents them from crystallizing. This allows the glass to appear to be a solid yet be transparent.

Heat of fusion

Heat of fusion is the amount of heat needed to melt one gram of a solid

heat of vaporization

Heat of vaporization is the amount of heat needed to vaporize one gram of a liquid at its boiling temperature

Density of Gas is

LOW, The density of a gas is about 1/1000 that of the same substance in the liquid state.

Why are liquids considered fluids?

Liquids are fluids because they have the ability to flow from one container to another and take the shape of the new container.

Molar enthalpy of fusion ( ΔHf )

Molar enthalpy of fusion ( ΔHf ) is the amount of energy required to melt one mole of a solid at its melting point.

Molar enthalpy of vaporization ( ΔHv )

Molar enthalpy of vaporization ( ΔHv ) is the amount of energy needed to vaporize one mole of a liquid at the liquid's boiling point under constant pressure.

sublimination

Sublimation is the process by which a solid changes to a gas, bypassing the liquid state. Examples include dry ice, moth balls, iodine, and ice at temperatures below 0°C.

Critical point

The critical point of a substance indicates the critical temperature and pressure

critical pressure

The critical pressure is the lowest pressure at which a substance can exist as a liquid at the critical temperature.

Critical temp

The critical temperature is the temperature above which a substance cannot exist in the liquid state.

Molar enthalpy of fusion for water

The molar enthalpy of fusion for water is 6.009 kJ/mol at one atmosphere of pressure.

Molar enthalpy of vaporization for water

The molar enthalpy of vaporization for water is 40.79 kJ/mol at one atmosphere of pressure.

Triple point

The triple point of a substance indicates the temperature and the pressure conditions at which the solid, liquid, and vapor of the substance can coexist at equilibrium.

freezing and boiling points of water

Water freezes at 0°C and boils at 100°C.

What is a phase change?

When a substance changes its physical state is called a phase change

What is a phase?

a phase is any part of a system that has uniform composition and properties.

amorphous solids

amorphous solids consist of particles that are randomly arranged

The kinetic-molecular theory of matter is

based on the idea that particles of matter are always in motion and this motion has consequences that affect its physical properties.

Boiling

boiling is the change of a liquid to bubbles of vapor that appear throughout the liquid

equilibrium

condition in which two opposing changes occur at equal rates (eg. liquid to gas = gas to liquid)

covalent-molecular crystals

covalent molecular crystals consists of covalently bonded molecules held together by intermolecular forces

covalent network crystals

covalent network crystals consists of atoms covalently bonded to their adjacent atoms such as diamonds & SiO2 (sand)

crystal lattice

crystal lattice is the representation of the arrangement of a crystal using a coordinate system

Crystal

crystalline solids consist of crystals, a substance in which the particles are arranged in an orderly, geometric, repeating pattern

Evaporation

evaporation is the process by which particles escape from the surface of a non-boiling liquid and enter the gas state

Freezing

freezing (solidification) is the physical change of a liquid to a solid by the removal of heat energy

ionic crystals

ionic crystals consist of positive & negative ions arranged in a regular pattern such as NaCl (salt) crystals

What is boiling?

is the conversion of a liquid to a vapor (gas) throughout all parts of the liquid.

equilibrium vapor pressure

is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature.

condensation

is the process by which a gas changes to a liquid.

crystal structure

is the total three-dimensional arrangement of particles of a crystal

volatile liquids

liquids that evaporate easily.

metallic crystals

metallic crystals consists of metal cations surrounded by delocalized valence electrons

boiling point

of a liquid is the temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure.

______ have definite shape and volume.

solids have a definite shape and a definite volume

unit cell

unit cell is the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice

Vaporization

vaporization is the process by which a boiling liquid changes to a gas