Intermolecular forces
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Chemists have to understand intermolecular forces to make sense of the properties of molecular compounds.
Intermolecular forces are somewhere between ten and a hundred times weaker than covalent bonds.
Intermolecular forces have a very important part to play in the properties and behaviour of biological molecules such a carbohydrates, proteins and nucleic acids.
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Tutorials
- Sorted FAQs on Intermolecular Forces
- Some exam "Dos and Don'ts": Intermolecular forces
- Intermolecular forces: audio tutorial
Webguides
Recently Asked Questions
- Hi. I'm wondering if there are dipole-dipole forces in phenols. If there are, how strong are they, in comparison with that in ketones? 170709
- Why is CH3F insoluble in water? if something like propanone is soluble whilst having only a C=O bond, why can hydrogen bonds form between water and the O from C=O but not between water and the F of C-F, when the C-F bond would be more polar than the C=O bond? 250509
- Hi. I am now working on an experiment concerning hydrogen bonds. I'm really perplexed about certain aspects and I hope you can give me some help. (i) I was told to measure the approximate strength of hydrogen bonds between ethanol molecules by adding different volumes of cyclohexane. Say, 20 cm3, 30 cm3 and 40 cm3 of cyclohexane were added to 10 cm3 of ethanol. And the point is the volume of ethanol used should be kept constant. What is the significance of keeping the volume of ethanol used constant and varying the volume of cyclohexane added? (ii)Since ethanol is a polar molecule whereas cyclohexane is non-polar, they are immiscible. So it is advisable to use 2 substances which are miscible, with only ethanol can form hydrogen bond to ensure all hydrogen bonds are broken. But is there any example? (iii)I was also told to investigate the hydrogen bonds formed between the ethyl ethanoate and trichloromethane. I wonder why hydrogen bonds can be formed between the ethyl ethanoate and trichloromethane but not between the ethyl ethanoate and 1,1,1-trichloroethane. (iv) During the course of experiment, the reactions were undertaken in an insulated glass beaker. Why can't a polystrene cup be used? Does cyclohexane or ethyl ethanoate dissolve the foam cup? (v) Further, the glass beaker should be dried before any experiment was done. Why shouldn't any water be present in the beaker? Do the hydrogen bonds in water affect the experimental results and if so, how will they be affected? 090109
Tests
updated: 09 July 2003
