Free Science courses

Learn It Check you know the main principles by reviewing the list of different topic areas, either click on the topic heading to quick learn the whole topic or pick individual principles to brush......

This page describes how the physical properties of substances having molecular structures varies with the type of intermolecular attractions - hydrogen bonding or van der Waals forces.......

This page looks at the information you can get from the mass spectrum of an element. It shows how you can find out the masses and relative abundances of the various isotopes of the element and......

This page explains the various ways that organic molecules can be represented on paper or on screen - including molecular formulae, and various forms of structural formulae. Molecular formulae......

This page explains how to work out the shapes of molecules and ions containing only single bonds. If you are interested in the shapes of molecules and ions containing double bonds, you will find......

This page explains how to find the relative formula mass (relative molecular mass) of an organic compound from its mass spectrum. It also shows how high resolution mass spectra can be used to find......

This page explains how the M+1 peak in a mass spectrum can be used to estimate the number of carbon atoms in an organic compound. Note: This is a small corner of mass spectrometry. It would be a......

The Falling Asleep ProcessDuring the day when we are a awake, our body and brain are working tirelessly to operate our body, and as they do so they slowly degrade at a cellular level. A person......

This page explains how the M+2 peak in a mass spectrum arises from the presence of chlorine or bromine atoms in an organic compound. It also deals briefly with the origin of the M+4 peak in......

This page explains the origin of the two weaker forms of intermolecular attractions - van der Waals dispersion forces and dipole-dipole attractions. If you are also interested in hydrogen......

This page explains the origin of hydrogen bonding - a relatively strong form of intermolecular attraction. If you are also interested in the weaker intermolecular forces (van der Waals......

This page describes what an infra-red spectrum is and how it arises from bond vibrations within organic molecules. The background to infra-red spectroscopy How an infra-red spectrum is produced......

Rossby waves are a belt of upper air westerlies which follow meanders around both hemispheres. The speed of these waves is not uniform. Within them are the very fast jet streams . Where, in......

Indicator SpeciesCertain species are capable of expressing characteristics that can indicate the state of the ecosystem they currently occupy. These species that can leave clues about the state of......

Barriers to entry are artificial barriers that deter potential new firms from entering the market. The types of barriers to entry are: Capital costs - high fixed costs of an industry Economies......

What Are Waves? Waves are vibrations that transfer energy from place to place without matter (solid, liquid or gas) being transferred. Think of a Mexican wave in a football crowd. The wave......

Cliffs Material is weathered from the cliffs and it then falls into the sea. If it is removed from the slope base by the waves then the cliff is vulnerable to erosion and therefore the waves energy......

Most beaches of composed of rock breakdown with varying proportions of biological material usually shell fragments. However if its an accumulation of material at the high tide mark the following......

Intermolecular forces are ones which act between molecules. There are 3 types of intermolecular forces: Instantaneous and Induced Dipoles The electrons in a molecule are constantly moving around......

Definitions Coast: The strip of land where it meets the sea Coastline: The margin of land. The limit to which wave action takes place. Shore: The strip of land lying between the high and low......