2.2.9 physical properties of covalent substances

what are the physcial properties mainly influenced by

intermolecular forces

what must be overcome to change state of a moleucle

intermoleuclar forces

the stronger the intermolecular forces…

the more energy needed to break them

why are many covalent structures liquid or gases at room temperature

becuse intermolecular forces are much weaker than covalent bonds

what 2 things does the strength of the intermolecular forces rely on

size of the molecule

polarity of the molecule

what is the principile for solubility

like dissolves like: non polar substances dissolve in non polar solutions, polar substances dissolve in polar solutions

what forms between non polar solutions and solvents when dissolved

london dispersion forces between solvent and solute molecules

what forms in polar solutions when dissolved

dipole-dipole interactions or the formation of hydrogen bonds between solvent and moleucles of solute

what happens to the solubility of molecules as their size increases

solubility decreases as the polar part of the molecule is a decreasingly small part of the whole molecule

why do giant covalent structures generally not dissolve in any solvents

the energy to overcome the strong covalent bonds is too great

what must a molecule have to conduct electricity

electrons or ions that are free to move

can covalent structures conduct electricity

no because have no delocalised electrons or free ions