Physical chemistry

thumb|right|300px|Electron transfer from a neutral lithium (Li) atom on the left to a neutral [[fluorine (F) atom on the right would give Li and F ions.]]

study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of laws and concepts of physics

homogeneous mixture composed of only one phase

In chemistry, a mixture is a material made up of two or more different chemical substances which can be separated by physical method. It is an impure substance made up of two or more elements or compounds mechanically mixed together in any proportion. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions or colloids.

An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water. Upon dissolving, the substance separates into cations and anions, which disperse uniformly throughout the solvent. Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved.

thumb|English chemist John Frederic Daniell|John Daniell (left) and physicist [[Michael Faraday (right), both credited as founders of electrochemistry]] Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typically an external electric circuit, but not necessarily, as in electroless plating) between electrodes separated by an ionically conducting and electronically insulating electrolyte (or ionic species in

electrical device that converts the energy of light directly into electricity by the photovoltaic effect

thumb|193x193px|Diamond and [[graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure.]]

thumb|upright=1.4|Mist and [[fog are aerosols|alt=photograph of heavy mist]]

alt=The solar wind moving through the magnetosphere alters the movements of charged particles in the Earth's thermosphere or exosphere, and the resulting ionization of these particles causes them to emit light of varying colour, thus forming auroras near the polar regions.|thumb|201x201px|The solar wind moving through the [[magnetosphere alters the movements of charged particles in the Earth's thermosphere or exosphere, and the resulting ionization of these particles causes them to emit light of varying color, thus forming auroras near the polar regions.]] Ionization or ionisation is the proce

state in which both reactants and products are present in concentrations which have no further tendency to change with time.There are no net changes in the concentrations of the reactant(s) and product(s). Such a state is known as dynamic equilibrium

reference values for temperature and pressure

Thermochemistry is the study of the heat energy which is associated with chemical reactions and/or phase changes such as melting and boiling. A reaction may release or absorb energy, and a phase change may do the same. Thermochemistry focuses on the energy exchange between a system and its surroundings in the form of heat. Thermochemistry is useful in predicting reactant and product quantities throughout the course of a given reaction. In combination with entropy determinations, it is also used to predict whether a reaction is spontaneous or non-spontaneous, favorable or unfavorable.

physical law that the pressure of a mixture of ideal gases is equal to the sum of the partial pressures of its constituents

branch of chemistry which develops and applies theoretical concepts

relationship in physical chemistry

branch of chemistry

thumb|An upturned vial of hair gel|241x241px thumb|Silica gel A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady state, although the liquid phase may still diffuse through this system.

hypothetical pressure of gas if it alone occupied the volume of the mixture at the same temperature

physical or chemical process

Vaporization (vapourisation in British English) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phenomenon, whereas boiling is a bulk phenomenon (a phenomenon in which the whole object or substance is involved in the process).

equilibrium constant as a measure of acid strength in solution

amount of energy released when an electron is attached to a neutral atom or molecule in the gaseous state to form a negative ion

weight per volume of a material

chemistry term; way of describing bonding in molecules or ions by the combination of several contributing structures into a resonance hybrid in valence bond theory

law of thermodynamics

electrostatic property of a molecule

a gas law that states that the amount of dissolved gas is proportional to its partial pressure in the gas phase

intensive physical property

phase of hydrogen

study of chemical reactions within the laws of thermodynamics

property of solutions that depend upon the ratio of the number of solute particles to the number of solvent molecules in a solution

chemical reaction where the reactants form products, which react together to give the reactants back

tendency of a substance to vaporize

chemical law that, if two elements form more than one compound, then the ratios of the masses of the second element which combine with a fixed mass of the first element will always be ratios of small whole numbers

used to describe or characterise elements' or compounds' readiness to form bonds

phenomenon where the boiling point of a liquid is higher when another compound is added

mathematical descriptions of molecular diffusion

single-step chemical reaction

thumb|500px|Gas–liquid absorption (a) and liquid–solid adsorption (b) mechanism. Blue spheres are solute molecules.

quantification of the electrical interactions between ions in solution

thumb|250px|The image on the left shows effusion, whereas the image on the right shows Molecular diffusion|diffusion. Effusion occurs through an orifice smaller than the mean free path of the particles in motion, whereas diffusion occurs through an opening in which multiple particles can flow through simultaneously.|alt=

measure of the effective concentration of a species in a mixture

ration of concentrations in a mixture at equilibrium

thumb|upright=1.5|Pump-probe techniques

In thermodynamics, the fugacity of a real gas is an effective partial pressure which replaces the ideal partial pressure in an accurate computation of chemical equilibrium. It is equal to the pressure of an ideal gas which has the same temperature and molar Gibbs free energy (chemical potential) as the real gas.

study of both physical and chemical phenomena that occur at the interface of two phases

dimensionless quantity

Behaviour of charged particles near a semi-permeable membrane

special electronic configuration of oxygen molecule

сonstant in crystallography

relocation of an electron from an atom or molecule to another

indicator which undergoes a definite color change at a specific electrode potential

thumb|upright=1.35|Pyrotechnic deflagrations Deflagration (Lat: de + flagrare, 'to burn down') is subsonic combustion in which a pre-mixed flame propagates through an explosive or a mixture of fuel and oxidizer. Deflagrations in high and low explosives or fuel–oxidizer mixtures may transition to a detonation depending upon confinement and other factors. Most fires found in daily life are diffusion flames. Deflagrations with flame speeds in the range of 1 m/s differ from detonations which propagate supersonically with detonation velocities in the range of km/s.

quantity of water contained in a material

technique in quantum chemistry

thermodynamic stability of a chemical system, quantitatively measured by relative molar standard Gibbs energies

abstract coordinate depicting chemical reaction progress

abnormal molecular mass

thumb|200px|Chemical structures of two synthetic polyelectrolytes, as examples. To the left is sodium polystyrene sulfonate|poly(sodium styrene sulfonate) (PSS), and to the right is [[polyacrylic acid (PAA). Both are negatively charged polyelectrolytes when dissociated. PSS is a 'strong' polyelectrolyte (fully charged in solution), whereas PAA is 'weak' (partially charged).]]