Intermolecular forces
Read our general notes on Risk Assessment
If possible can you just give me examples of substances that would have: van der Waals' forces, hydrogen bonding, permanent dipoles and dipole-dipole attractions.
130408
Corrie writes ....
van der Waals' forces only: between non-polar molecules, such as hydrocarbons, halogens, Noble Gases, CO2 etc
Hydrogen bonding: between molecules that contain a H-atom attached to a F, O or N atom, such as H2O, HF, NH3, H2O2, CH3OH etc
Dipole-dipole forces: between molecules that are polar, i.e have a permanent overall dipole, such as H-Cl, H2C=O, OF2 etc.
REMEMBER that:
1. All molecules, whether non-polar or polar, experience attraction due to van der Waals' forces but for small molecules this contribution to the attraction is usually less than that from dipole-dipole attraction, and much less than that from H-bonding, if also present.
2. Small molecules capable of hydrogen bonding are usually also polar, e.g. H2O and will experience dipole-dipole attraction and van der Waals' forces as well, but the H-bonding attraction is by far the strongest attraction.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
Rate this page or react
Share your views on this page, 1 ratings so far
, rated at 
updated: 13 April 2008
