Hydrogen bonds are not chemical bonds, but rather non-covalent interactions between a hydrogen atom from one molecule and an electronegative atom (such as nitrogen, oxygen, or fluorine) from another molecule. The strength of hydrogen bonds can vary depending on the electronegativity of the atoms involved and the molecular environment, but typically they range from 1 to 40 kJ/mol, significantly weaker than covalent bonds which typically have bond strengths in the range of 100 to 1000 kJ/mol.