Chemistry

Molar mass

The mass in grams of one mole of that substance

Molar concentration

The amount of solute per unit volume of solution

Electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons

V

v

Heat of a reaction

The net change of chemical potential energy of the system

Exothermic reactions

Reactions which transform chemical potential energy into thermal energy

Endothermic reactions

Reactions which transform thermal energy into chemical potential energy

Activation energy

The minimum energy required to start a chemical reaction.

Activated complex

A high energy, unstable, temporary transition state between the reactants and the products.

Reaction rate

The change in concentration per unit time of either a reactant or product

Catalyst

A substance that increases the rate of the reaction but remains unchanged at the end of the reaction.

Closed system (in chemistry)

One in which mass is conserved inside the system but energy can enter or leave the system freely

Open system (in chemistry)

One in which the both the energy and matter can be exchanged between the system and its surroundings

State Le Chatelier’s principle

When an external stress (change in pressure, temperature, or concentration) is applied to a system in dynamic chemical equilibrium, the equilibrium point will change in such a way as to counteract the stress.

Acid

A proton donor

Base

A proton acceptor

Ionization

The reaction of a molecular substance with water to produce ions

Strong acid

An acid that ionizes almost completely in an aqueous solution

weak acid

An acid that only ionizes partially in an aqueous solution

Dissociation

The splitting of an ionic compound into its ions

Strong base

A base that dissociates almost completely in an aqueous solution

Weak Base

A base that only dissociates/ionizes partially in an aqueous solution

Amphoteric substance

A substance that can act either an acid or a base

Salt

A substance in which the hydrogen of an acid has been replaced by a cation

Hydrolysis of a salt

A reaction of an ion (from a salt) with water

Neutralization

A chemical reaction in which an acid and a base react so that neither is in excess

Standard solution

A solution of known concentration

Redox reaction

A reaction involving the transfer of electrons

Oxidation

The loss of electrons

Reduction

The gain of electrons

Oxidizing agent

A substance that accepts electrons

Reducing agent

A substance that donates electrons

Anode

The electrode where oxidation takes place

Cathode

The electrode where reduction takes place

Electrolyte

A substance that can conduct electricity due to the presence of free (mobile) ions when molten or dissolved in solution.

Describe a Galvanic cell

An electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy.

Describe an electrolytic cell

An electrochemical cell that uses electrical energy to cause a non-spontaneous redox reaction to occur. Thus, electrical energy is converted into chemical energy.

Hydrocarbon

A compound containing only carbon and hydrogen atoms

Saturated compound

A compound in which all of the bonds between carbon atoms are single bonds.

Unsaturated compound

A compound in which there is at least one double and/or triple bond between carbon atoms.

Functional group

An atom or group of atoms that form the center of chemical activity in the molecule

Homologous series

A series of similar compounds which have the same functional group and have the same general formula, in which each member differs from the previous one by a single CH2 unit

Structural isomers

Compounds having the same molecular formula but different structural formulae.

Describe organic molecules

Molecules containing carbon atoms