Topic 2 : Intermolecular Interactions Flashcards
State what is meant by the term electronegativity and hence explain the polarity, if any, of the binds in chlorine triflouride ClF3
The ability of an atom to attract a bonding pair of electrons in a covalent bond
Fluorine is more electronegative than chlorine
F= delta - Cl = delta +
In terms of atomic structure, give two reasons why oxygen is more electronegative than carbon
Oxygen has more protons so a greater nuclear charge
Oxygen has a smaller atomic radius than the carbon atom
Explain why CO2 is non polar
It is symmetrical so the bond polarities cancel out
Explain why bromine is less volatile than chlorine
Bromines instantaneous dipole - induced dipole attractions are stronger as bromine had more electrons
Water might be expected to have a lower boiling temperature than hydrogen sulfide but it actually has a higher boiling temperature
Comment on this statement by referring to the intermolecular forces in both theses substances
A lower boiling point of water was expected as water has fewer electrons than hydrogen sulfide
Water has weaker instantaneous dipole - induced dipole interactions
Water has a higher boiling point because it has hydrogen bonding
Hydrogen binding stronger than London forces so requires more energy to break
Explain why isomers of hexane have lower boiling temperatures and so are found in the petrol fraction
Isomers in petrol fraction have branched chains
Branched chains have lower surface area
London forces are weaker so boiling point is lower
Methanol CH3OH is miscible in water in all proportions
Sodium chloride is much less soluble in methanol than in water
Explain the statements using your knowledge of the interactions between solutes and solvents
Hydrogen bonding between water and methanol
Same strength of bonding in either component on its own
Hydration of sodium and chlorine
The ionic bonding is stronger than the bonding between sodium and chlorine ions and methanol
