Chemical bonds have a certain stability based on the type of bonding. Some
bonds are quite strong The following are covalent bond strengths.
Bond Bond Strength(kJ/mole); Bond Bond Strength (kJ/mole)
Cl-Cl 239 H-Cl 427
H-H 432 C-H 413
N N 941 N-H 391
Bond strength can be overcome by adding heat...The GC and AT bonds in DNA
are hydrogen bonds (non-covalent) and can also be overcome with heat.
these hydrogen bonds are about 71 kilojoules per mole...relatively weak (but
strong in large numbers) and can be broken and reformed by heating and
cooling. This is the secret behind the polymerase chain reaction.
Faletra, Peter, Argonne National Labs
care to translate that?