Energetics definitions

This is from the interactive syllabus. Remember for standard values you must state under standard conditions i.e. 25 0C 1 atm and any solutions 1 mol/dm3.

Energy Definitions

It should be noted that many of the energy definitions can be considered in the reverse direction with a corresponding change of sign for the energy. Bond formation = exothermic ΔH negative, bond cleavage = endothermic ΔH positive

Enthalpy of vaporisation

The energy required to vaporise one mole of a liquid

Enthalpy of atomisation

The energy required to produce one mole of gaseous atoms from an element in its standard state

Bond dissociation enthalpy

The energy change when one mole of a specific bond is broken or created

Bond enthalpy

The average energy change when one mole of a specific type of bond is broken or created.

Enthalpy of Combustion

The energy released when one mole of a compound is burned in excess oxygen

Enthalpy of formation

The energy change when one mole of a compound is formed from its constituent elements in their standard states

Enthalpy of solution

The energy change when one mole of a substance is dissolved in an infinite amount of water

Hydration enthalpy

The energy change when a particle is taken from infinite separation in the gaseous state to its position in an aqueous lattice

1st Ionisation energy

The energy required to produce one mole of gaseous ions from one mole of gaseous atoms by removal of one mole of electrons

Lattice enthalpy

The energy change when one mole of an ionic substance is broken into its constituent atoms at infinite separation.

Energetics Useful links

The following are some useful chemguide links:

Definitions

Using bond enthalpies

using Hess's law

Using specific heat capacities

Homework- using Bond energies

Please finish the sheet on bond energies. Also read the next part in your book so that you are ready for the lessons after academic travel. Hess's law and Born Haber cycles.

Have a good week.

Allotropes of carbon

The following video is interesting about the possible future of graphene:

Bonding test

We have just about finished the topic on bonding so please start revising for a test next week. Your notes, experiments and textbook should be used. In addition the IB website is useful too. Here are the following links:

IBbonding standard level

IB bonding higher level

Bonding Useful Links

Shapes

Shapes and angles

Sigma and pi bonds

Hybridisation video clip

Delocalisation of electrons

Bonding in methane

Bonding in ethene

Bonding in ethyne

Bonding in benzene

Welcome back

Hi, I hope that you all have had a great Christmas and New Year. Cran Montana is sunny with lots of snow at the moment. :)

Please look at the following links, in preparation for the next topic, bonding.

Bonding IB site

Bonding Chem Guide