As the strength of intermolecular forces increases, the temperature of an ideal gas decreases. At lower temperatures, molecules are more likely to move around randomly. As the temperature increases, they are more likely to remain in place and collide with one another more frequently. Because the number of molecules in an ideal gas is constant, their speed (and hence kinetic energy) increases as temperature increases.
When intermolecular forces increases, physical properties can become less stable. In liquids, for example, as intermolecular forces increase, the liquids become more viscous (sticky). In solids, as intermolecular forces increase, the crystals may become less stable and may melt. In gases, intermolecular forces can make gas more or less soluble in other gases, as the molecules repel each other and try to stay apart. As A result :
1. Melting Point increases
2. As the IM forces increase, it makes it harder for the molecules to escape from the liquid; therefore, the vapor pressure must decrease.
3. Boiling Point increases
4. As intermolecular forces continue to increase, it becomes more difficult for the particles to slide across each other; therefore, viscosities must therefore also increase.
5. When the forces between molecules are increased, the molecules become more attracted to each other and this means that the surface tension increases.
