Salt has a higher melting point than sugar because ionic bonds are stronger than covalent bonds.
Salt has a higher melting point than sugar because ionic bonds are stronger than van der Waals' forces.
Covalent network solids usually have very high melting points because covalent bonds are strong.
As ∆vapH increases, boiling point increases.
Branched-chain alkanes have lower boiling points than their straight-chain isomers.
Straight-chain alkanes have lower boiling points than their branched-chain isomers.
Molecules with permanent dipoles will have stronger van der Waals' forces than similar molecules with temporary dipoles.
The strength of electrostatic forces increase with distance.
When molecules are large the van der Waals' forces between them are strong.
Small molecules have strong van der Waals' forces between them because their charge density is high.
Cis isomers often have higher melting points than their trans equivalents when the cis form is polar.
Cis isomers have lower melting points than their trans equivalents because their molecules are unable to fit together closely.
Hydrogen bonding makes a small difference to the melting and boiling points of solids.
Hydrogen bonding occurs in any molecule containing hydrogen atoms and oxygen, nitrogen or fluorine atoms.
Hydrogen bonding occurs when hydrogen atoms are bonded to electronegative elements such as O, N or Cl.
Hydrogen bonding is the reason fluorocarbons affect the ozone layer.
Hydrogen bonding accounts for the unusually high boiling point of water.
Without hydrogen bonding, protein molecules would not hold their characteristic shapes.
Propanone is soluble in water because hydrogen bonds form between water molecules and the oxygen atom.
Molecules which are able to form multiple hydrogen bonds will have higher boiling points than those able to form only a single hydrogen bond.
Hydrogen bonding accounts for the high surface tension of water.
The closer molecules can fit together, the stronger the van der Waals' forces between them.
Van der Waals' forces between non-polar molecules are sometimes known as dispersion forces.
Van der Waals' forces between non-polar molecules are sometimes known as London forces.
Hydrogen bonding is a form of van der Waals' force.
Hydrogen bonding can be thought of as the sharing of a proton between two highly-electronegative atoms.
A hydrogen bond is about 50% the strength of a covalent bond.
Hydrogen bonds are about 10% the strength of covalent bonds.
Hydrogen bonds are about 1% the strength of a covalent bond.
Ice floats on water because the water molecules within the crystal are held apart by hydrogen bonds.
Solid wax sinks in molten wax due to hydrogen bonding.
Ammonia has an unusually low boiling point due to hydrogen bonding.
HCl has a higher boiling point than HF because of hydrogen bonding.
As ∆fusH decreases, melting point increases.