intermolecular forces Flashcards
inorganic chemistry of group 7 (11 cards)
How do London forces occur between molecules
There is an uneven distribution of electrons around the molecule, which then creates an uneven distribution of charge. This creates a temporary dipole in the molecule, which induces dipoles in neighbouring molecules.
what is permanent dipole-dipole interaction
The electrostatic attraction between oppositely charged permanent dipoles of neighbouring molecules.
what are hydrogen bonds.
Hydrogen bonds are the electrostatic attraction between electrons deficient hydrogens and a highly electronegative atom ( N, O, F )
why do the boiling and melting points of alkanes increase as the length of the carbon chain increase.
alkanes only have London forces between them, so the longer chain alkane have more electrons and a larger surface area to interact with each other, therefor have more London forces so more heat energy is needed to break these forces.
why dose branching in alkanes lower the boiling poin.
branches decrease surface area, so there is less contact with other molecules, so less London forces, so less energy needed to break them.
What is volatility
describes the ease of a substance to vaporize
what is the relationship between the enthalpy change of hydrogen of an ion and its solubility in water
the more exothermic the enthalpy change of hydration of an ion, the greater its solubility in water.
Why are some covalent molecules insoluble in water.
molecules that are non-polar or have a very small polar charge on them are insoluble in water because they do not form interactions with the polar water molecules.
To identify if the substance will be soluble in a particular solvent or not, the substance should have……
similar intermolecular forces to the solvent that it’s being dissolved in.
having hydrogen bonds creates high solubility and high boiling points.
period.
