U1-3-4 - Bonding and Attractions in Compounds Flashcards
Part of the Structure and Bonding topic from Unit 1 of Higher Chemistry, Chemical Changes and Structure
To fairly compare the m.p./b.p. of two molecules, they should have _______________ so that they have similar LDF strength.
To fairly compare the m.p./b.p. of two molecules, they should have the same no. of electrons so that they have similar LDF strength.
Additional electrostatic forces of attraction between polar molecules.
(Additional = on top of LDFs)
Permanent dipole-permanent dipole interactions
PD-PDIs for short
To fairly compare the m.p./b.p. of two molecules, they should have the same no. of electrons so that they have ___________.
To fairly compare the m.p./b.p. of two molecules, they should have the same no. of electrons so that they have similar LDF strength.
Permanent dipole-permanent dipole interactions
Additional electrostatic forces of attraction between polar molecules.
(Additional = on top of LDFs)
Electrostatic forces of attraction between molecules that contain the highly polar N-H, F-H or O-H bonds.
Hydrogen bonds
Weakest type of van der Waals force
London dispersion forces
Hydrogen bonds
Electrostatic forces of attraction between molecules that contain the highly polar N-H, F-H or O-H bonds.
NH3, H2O and HF have unusually high boiling points. Why?
They have hydrogen bonds between their molecules. These require more energy to break than other van der Waals forces.
Both molecules have the same no. of electrons.
Which one has the higher b.p. and why?
Ethane-1,2-diol - more H-bonds per molecule
or per mole
Both have the same no. of electrons. Why does propan-1-ol have the higher b.p.? (2)
Ethanethiol only has weaker PD-PDIs, propan-1-ol has hydrogen bonds (1)
Hydrogen bonds take more energy to break (1)
Why is ice less dense than liquid water?
Hydrogen bonding between molecules (creates a less dense structure in ice than in liquid water)
Strongest type of van der Waals force
Hydrogen bonding
