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The enthalpy change for a reaction is the same whether it occurs in one step or a series of steps.

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Fluids

Substances that flow freely, gases and liquids.

Activation Energy

Amount of energy that must be absorbed by reactants in their ground states to reach the transition state so that a reaction can occur. In other words, activation energy is the minimum energy required for a chemical reaction to occur.

Free Radical

A highly reactive chemical species carrying no charge and having a single unpaired electron in an orbital.

Mass Action Expression

For a reversible reaction, aA + bB cC + dD the product of the concentrations of the products (species on the right), each raised to the power that corresponds to its coefficient in the balanced chemical equation, divided by the product of the concentrations of reactants (species on the left), each raised to the power that corresponds to its coefficient in the balanced chemical equation. At equilibrium the mass action expression is equal to K, at other times it is Q.[C]c[D]d [A]a[B]b = Q, or at equilibrium K.

Nuclear Reaction

Involves a change in the composition of a nucleus and can evolve or absorb an extraordinarily large amount of energy.

Enthalpy

The heat content of a specific amount of substance, defined as E= PV.

Formula

Combination of symbols that indicates the chemical composition of a substance.

 

Metal

An element below and to the left of the stepwise division (metalloids) in the upper right corner of the periodic table, about 80% of the known elements are metals.

Foam

Colloidal suspension of a gas in a liquid.

Essential Oil

A plant extract that has a distinctive odour or flavour.