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A brownish smog occurring in urban areas receiving large amounts of sunlight, caused by photochemical (light-induced) reactions among nitrogen oxides, hydrocarbons and other components of polluted air that produce photochemical oxidants.

 

Latest Articles

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Chemical Change

A change in which one or more new substances are formed.

Electrolyte

A substance whose aqueous solutions conduct electricity.

 

Emission Spectrum

Spectrum associated with emission of electromagnetic radiation by atoms (or other species) resulting from electronic transitions from higher to lower energy states.

 

Crystal Lattice Energy

Amount of energy that holds a crystal together, the energy change when a mole of solid is formed from its constituent molecules or ions (for ionic compounds) in their gaseous state.

Ketone

Compound in which a carbonyl group is bound to two alkyl or two aryl groups, or to one alkyl and one aryl group.

Capillary Action

The drawing of a liquid up the inside of a small-bore tube when adhesive forces exceed cohesive forces, or the depression of the surface of the liquid when cohesive forces exceed the adhesive forces.

Compressed Gas

A gas or mixture of gases having, in a container an absolute pressure exceeding 40 psi at 21.1°C (70°F)

Voltaic Cells

Electrochemical cells in which spontaneous chemical reactions produce electricity, also called galvanic cells.

 

Supercritical Fluid

A substance at temperature above its critical temperature.

Melting Point

The temperature at which liquid and solid coexist in equilibrium, also the freezing point.