Definitions

First Ionisation Energy

Energy required to remove one mol of electron from 1 gaseous mol of an atom

Successive ionisation energies

Energy required to remove 1 mol of electron from 1 gaseous mol of ion (e.g. Ba+ —→ Ba2+ + e-)

Periodicity

Repeating trends or patterns in physical or chemical properties across a period.

Relative ATOMIC Mass

Mean weighted mass of an atom compared to 1/12th of a carbon-12 atom

Relative ISOTOPIC Mass

Mass of an isotope compared to 1/12th of a carbon-12 atom

Relative MOLECULAR Mass

Weighted mean mass of a molecule compared to 1/12th of a carbon-12 atom

Enthalpy of COMBUSTION

Energy required to completely combust 1 mol of a substance in standard conditions

Enthalpy of FORMATION

Energy required to form 1 mol of a substance, in standard conditions

Enthalpy of NEUTRALISATION

Energy required to produce 1 mol of H2O in a neutralisation reaction

Enthalpy of REACTION

Energy required to form the products of any balanced reaction

What are standard conditions?

• Temp - 298 K

• Pressure - 100kPa

• All reactants and products are in standard states

Electronegativity

An atom’s tendency to attract a electron pair in a covalent bond.

Activation Energy

Minimum energy required to start a reaction

Homologous Series

Group of hydrocarbons/organic molecules that share similar chemical properties and the same functional group

Functional Group

Atom or molecule (part of the organic molecule), that defines its chemical/physical properties (e.g. Alcohols are soluble in water due to the hydroxyl group)

Structural Isomerism

When 2 molecules have the same molecular formula, but a different structural formula

Whether the molecule is straight-chained or branched

Positional Isomerism

2 molecules have the same molecular formula, but the functional group is in a different place

Stereoisomerism

2 molecules that have the same molecular formula, but a different orientation in 3D space. This usually is due to a double bond, which leads to restricted rotation.

E / Z Isomerism

Z(Cis) - when the 2 different groups are on the same plane (from carbon POV)

E(Trans) - when the 2 different groups are on different planes

Name bonds, from strongest to weakest

Ionic Bonds

Covalent bonds

Permanent-dipole-dipole interactions

Induced-dipole-permanent-dipole interactions

Hydrogen bonds

Average bond enthalpy

average enthalpy change that takes place when breaking 1 mol of a given type of bond in molecules of gaseous species via homolytic fission

Hess’ Law

If a reaction can take place by more than one route (and initial and final conditions are the same), the enthalpy change is the same.

Dynamic Equilibria

• Closed system

• Rate of forward reaction is the same as the rate of backwards reaction

• Amount of products and reactants is constant

Le Chatelier’s Principle

If the conditions of dynamic equilibrium are disturbed, the positions of equilibrium will shift to counteract the change made.

What is Kc

Ratio for concentration of products to reactants

Is only affected by temperature

[C]c x [D]d / [B]b x [A]a

Same formula is used for units as well

Aliphatic

Organic molecule that doesn’t have an aromatic ring

Aromatic

Organic molecule that does have an aromatic ring

Alicyclic

Organic molecule that doesn’t have an aromatic ring, and also has a closed structure.

Homolytic fission

2 radicals are formed by splitting the bond evenly, so each atom gets 1 electron each

Heterolytic fission

2 ions are formed, as the bond is split unevenly. One atom gets both electrons ,forming cations and anions