Polar Bonds Part 2 Flashcards
What is the relationship between molecular mass and boiling point?
As molecular mass increases, boiling point increases
What is dipole-dipole bonding?
Electrostatic interactions between permanent dipoles in molecules, whereby the slightly negative end of one molecule will attract to the slightly positive end of its neighbour
What is hydrogen bonding?
The attraction between polar molecules, in which hydrogen is bound to a period 2 electronegative atoms, such as N, O or F
How does the strength of hydrogen bonding increase?
The strength of the molecules increase as they become more closely packed together
What is graphite?
The only example of a 2D covalent network, with each carbon atom bonded to 3 adjacent atoms, with one delocalised electron
What are the unique properties of water and how can they be explained?
Water has a high boiling point, high surface tension and expands upon freezing, which can be explained by its hydrogen bonding
What occurs when covalent molecular compounds are heated?
The weaker intermolecular bonds are broken first
What is an example of ion-dipole bonding?
When salt dissolves in water, the sodium and chloride ions and the polar water molecules are attracted to each other by ion-dipole interactions
Give an example of the strength of ion-dipole bonding?
It is strong enough to overcome attractions within lattices
Do non-polar molecules have dispersion forces?
Non-polar molecules have no permanent dipole
How is a temporary dipole produced?
Electrons move around the atom and are occasionally unbalanced
What are dispersion forces?
Temporary weak bonds with neighbouring molecules which exist for all substances
How do dispersion forces increase?
With increasing size of molecules, due to more electrons
What is the difference in electronegativity between atoms in order for a non-polar covalent bond to be formed?
0-0.4
What is the difference in electronegativity between atoms in order for a polar covalent bond to be formed?
0.5-1.7
