Lesson 5 - Gases, Liquids, and Solids

Gaseous State

Molecules far apart and disordered

Negligible interactions between molecules

Liquid State

Intermediate Situation

Molecules move past each other

Travel more slowly than Gaseous State

Solid State

Molecules move very slowly or no at all

Strong interaction between molecules

Boiling Point

The temperature at which a liquid changes to a gas

Melting Point

The temperature at which a solid becomes a liquid

Gas Pressure

results from the force exerted by a gas per unit surface area of an object

Barometer

An instrument that measures atmospheric pressure

Millimeter of Mercury

a common unit of pressure

Torr

a unit of pressure equal to 1 mmHg that is named in the honor of Evangelista Torricelli, the one who invented the barometer

Atmosphere (atm)

average pressure at sea level which is 760 mmHg

Pascal

SI unit of pressure

Manometer

instrument for measuring pressure in a container

Boyle's Law

States that for a fixed mass of ideal gas at a constant temperature, the volume of gas is inversely proportional to the applied pressure.

Boyle's Law

P1V1=P2V2

Charles' Law

States that the volume of a fixed mass of an ideal gas at a constant pressure is directly proportional to the temperature in Kelvin.

Charles' Law

V1/T1 = V2/T2

Gay Lussac's Law

states that for a fixed mass of a gas at constant volume, the pressure is directly proportional to the temperature in Kelvin

Gay Lussac's Law

P1/T1=P2/T2

Combined Gas Law

P1V1/T1=P2V2/T2

Combined Gas Law

the relationship between the pressure, volume, and temperature of a fixed amount of gas

Avogadro's Law

equal volumes of gases at the same temperature and pressure contain equal numbers of molecules

Standard Temperature and Pressure (STP)

A temperature of 273 K and a pressure of 1.00 atm

Ideal Gas Law

PV=nRT

Ideal Gas Constant

0.0821 Latm/molK

Dalton's Law of Partial Pressures

states that the total pressure of a mixture of gases is the sum of the partial pressures of each individual gas

Partial Pressure

pressure of each gas in a mixture of gases would exert if it were alone in the container

Kinetic Molecular Theory

Relationship between the observed behavior of gases and the behavior of individual gas molecule within the gas can be explained by __________

Condensation

Gas to liquid

Solidification

liquid to solid

London Dispersion Forces

extremely weak attractive forces between atoms or molecules caused by the electrostatic attraction between temporary induced dipoles

Intermolecular force that exists between all molecules.

Fritz London

london dispersion forces were discovered by

dipole-dipole dispersion

The attraction between the positive end of the dipole of one molecule and the negative end of another dipole in the same or different molecule

Hydrogen Bonding

intermolecular force of attraction between the partial positive charge on a hydrogen atom bonded to an atom of high electronegativity, most commonly O, N and F

Surface Tension

It is directly related to the strength of the intermolecular attraction between its molecules.

Surface Tension

It is defined as the energy required to increase the surface area of the liquid.

Vapor Pressure

the partial pressure of a gas in equilibrium with its liquid form in a closed container

Vapor

Gaseous state of a substance that is a liquid or a solid at room temperature

Equilibrium

A condition in which two opposing processes occur at an equal rate

Vapor Pressure

It is a physical property of the liquid and a function of temperature.

Relative Humidity

The ratio of the actual partial pressure of the water vapor in the air, to the equilibrium vapor pressure of water at the relevant temperature.

Boiling Point

The temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure

Normal Boiling Point

The temperature at which liquid boils under a pressure of 1 atm

Factors Affecting Boiling Point

Intermolecular Forces, Number of sites for intermolecular interaction (surface area) and molecular shape

Crystallization

The formation of solid from a liquid

Crystalline Solids

Those whose atoms, ions or molecules have an ordered arrangement extending over a long range

Amorphous Solids

randomly arranged particles that have no ordered long-range structures.

Ionic Solids

It consist of orderly arrays of ions held together by ionic bonds in a crystal latttice

Molecular Solids

It consist of atoms or molecules held together by intermolecular forces.

Metallic Solids

It consist of metal atoms surrounded by valence electrons

Allotropes

two or more different molecular forms of the same element in the same physical state

Polymeric Solid

Giant molecules, can be crystalline, semi crystalline or amorphous, common examples are rubber, plastics and proteins

Network Solid

a solid in which a very large number of atoms are linked by covalent bonds

Phase Change

a change from one state (solid or liquid or gas) to another without a change in chemical composition

Phase

It is any part of a system that looks uniform (homogenous) throughout.

Heat Fusion

The heat necessary to melt 1.0 g of any solid

Heat of Vaporization

The heat necessary to vaporize 1 g of liquid at its normal boiling point

Heating Curve

A plot of the temperature versus time

Reversible

An important aspect of these phase changes is that each one of them is __________.

Sublimation

the process in which a solid changes directly into a gas

Triple Point

the unique set of conditions at which all three phases of a substance are equally stable and in equilibrium