Chemistry: 5 - Chemical Energetics

to be edited!! some are wrong

Standard Enthalpy Change of Reaction

The enthalpy change when molar quantities of reactants as specified in the chemical equation react to form products at 298K and 1 bar.

Standard Enthalpy Change of Formation

The enthalpy change when 1 mol of a substance is formed from its constituent elements in their standard states at 298K and 1 bar.

Standard Enthalpy Change of Combustion

The heat evolved when 1 mol of a substance is completely burnt in excess oxygen at 298K and 1 bar.

Standard Enthalpy Change of Neutralisation

The heat evolved when 1 mol of water is formed in the neutralisation reaction between an acid and a base at 298K and 1 bar.

Standard Enthalpy Change of Hydration

The heat evolved when 1 mol of a substance is dissolved in an infinite volume of water at 298K and 1 bar.

Standard Enthalpy Change of Solution

The enthalpy change when 1 mol of a solute is dissolved in an infinite volume of solvent at 298K and 1 bar.

Hess’s Law

The enthalpy change of a reaction is determined by its initial and final states and is independent of the pathway taken.

Bond Energy

The amount of energy needed to break 1 mol of covalent bonds in the gaseous state at 298K and 1 bar.

Standard Enthalpy Change of Atomisation

The energy required when 1 mol of gaseous atoms is formed at 298K and 1 bar.

Lattice Energy

The heat evolved when 1 mol of a solid compound is formed from its constituent gaseous ions at 298K and 1 bar.

Ionisation Energy (First)

The amount of energy needed to remove 1 mol of electrons from 1 mol of gaseous atoms to form 1 mol of singly charged gaseous cations.

Electron Affinity

The enthalpy change when 1 mol of electrons is added to 1 mol of gaseous atoms to form 1 mol of singly charged gaseous anions.

Entropy

A measure of the disorder in a system, reflected in the number of ways the energy in a system can be distributed through the motion of its particles.

Standard Gibbs Free Energy Change

The Gibbs free energy change needed to convert reactants to products at 298K and 1 bar.

Equation for Gibbs Free Energy Change

ΔG = ΔH - T(ΔS)

Equation for L.E.

(q+ x q-) / (r+ + r-)

Heat Capacity Formula

q = mcΔT

Heat Capacity and Enthalpy Change Formula

ΔH = q / n