My lesson

Dynamic equilibrium

The rates of the forward and reverse reactions are equal

Kinetic energy

The energy associated with moving particles

Concentration

The amount of solute dissolved in a solution

Le Chatelier's Principle

States that a disturbance to the equilibrium will result in the system adjusting to compensate for the change, and equilibrium is re-established. Some changes include temperature, concentration or pressure.

Catalyst

A substance that increases the rate of a reaction without itself being consumed in the reaction (also lowers activation energy, thus the reaction reaches equilibrium quicker)

Equilibrium constant (Kc)

Only temperature can affect the value of Kc*

Self-ionisation of water

The reaction in which a water molecule loses a hydrogen ion to become a hydroxide ion (OH-) and the hydrogen ion immediately reacts with another water molecule to form a hydronium ion (H3O+)

Esterification

A condensation reaction between a carboxylic acid and alcohol that generates an ester

Proton donor

A substance that can donate H+

Monoprotic

An acid that can donate only one hydrogen ion per molecule

Polyprotic

An acid that can donate more than one hydrogen ion per molecule

Strong base

A base that completely ionises in water

Weak base

A base that doesn't completely ionise in water

Alkaline

Basic solution

Hydroxyl

A functional group consisting of an -OH group, which is an oxygen atom and a hydrogen atom joined by a single bond

Carboxylic acid

A class of organic compound that contains a carboxyl functional group

Electrical conductivity

The degree to which a material conducts an electric current

Strength

The level of dissociation of an acid or a base

Strong acid

An acid that completely ionises in water

Weak acid

An acid that does not completely ionise in water

Ionic product constant of water (Kw)

The equilibrium constant for the self-ionisation of water

pH

A measure of hydrogen ion concentration in a solution and therefore a measure of the acidity or alkalinity of a solution

Limiting reagent

The reactant in a chemical reaction that determines how much product is made

Conjugate base

A base formed by removing an H+ from an acid

Conjugate acid

An acid formed when a base accepts an H+

Amphiprotic

A molecule or an ion that can either donate or accept a proton and therefore can act as an acid or a base

Buffer solution

A solution that resists changes in pH when small quantities of acids or alkalis are added

Titration

The addition of a solution of known concentration to a known volume of another solution of unknown concentration until the reaction reaches neutralisation

Titration curve

A graph of pH against volume of reactant added

Acid dissociation constant (Ka)

The equilibrium constant for the dissociation of an acid in aqueous solution

Base dissociation constant (Kb)

The equilibrium constant for the dissociation of a base in aqueous solution

Indicator

A chemical substance that changes colour at different pH values

pKa

A measure of acid strength; the negative common logarithm (to base 10) of an acid dissociation constant

End point

The point in a titration when the indicator changes colour

Equivalence point

The point in a titration when the reactants have reacted in the molar ratio of the balanced chemical equation

Standard solution

A solution of accurately known concentartion

Volumetric analysis

A quantitative analytical technique for determining the concentration of a solution by titrating it against another solution of known concentration

Half-equivalence point

A point in a titration curve where the concentration of the titre is equal to half the original concentration of the analyte; also called the midpoint

Buffer region

The section of a titration curve is relatively flat because adding more acid or base does not drastically affect the pH

Analyte

A solution of unknown concentration

Oxidation Reaction

An organic reaction involving the gain of oxygen atoms and/or the loss of hydrogen atoms.

Redox

A chemical reaction involving the transfer of electrons from one reactant to another

Oxidise

To lose electrons

Reducing Agent

A reactant that causes another reactant to gain electrons and be reduced and is itself oxidised.

Oxidising Agent

A reactant that causes another reactant to lose electrons and be oxidised and is itself reduced

Redox Reaction

A reaction involving oxidation of one reactant and reduction of the other reactant

Cathode

The electrode where reduction occurs

Polarity

The change of an electrode, either positive or negative

Electrode

A solid conductor of electricity either into or out of a half-cell

External circuit

The electric circuit (wires) that allows electron movement from anode to cathode.

Salt bridge

An electrical connection between the two half-cells in a galvanic cell; it allows for the flow of charge by moving ions to the cathode and anions to the anode

Half-cell

Half of an electrochemical cell, where either oxidation or reduction occurs

Internal Circuit

The part of an electrochemical cell that allows for ion flow, e.g. the salt bridge

Cell Diagram

A diagram of a galvanic cell that has all the key components, reaction mechanisms and electron/ion movement labelled

Fuel Cell

A galvanic cell that produces electricity by using a constant supply of reactants (often hydrogen and oxygen) and inert electrodes that don't break down

Inert Electrode

An electrode that conducts electricity in the half-cell, but doesn't participate in the reaction, i.e. it's neither a reactant nor product

Alkaline Fuel Cell

A fuel cell that consumes hydrogen and oxygen, producing water, heat and electricity

Standard Electrode Potential

The electrical potential that an electrode generates under standard conditions

Standard Conditions

The conditions under which all E^0 values are measured: 25 °C, 1 atm and 1M electrolyte.

Cell Potential Difference

The electrical potential difference (V) between two electrodes; the voltage that the galvanic cell can generate under standard conditions.

Electromotive Force (EMF)

The difference in potential across a cell that generates electricity.

Molten

A substance that has been melted to form a liquid

Electrolyte

A substance that conducts electricity when melted or dissolved in a solution.