Question

Which are stronger, intermolecular or intramolecular forces for a given molecule? What observation(s) have you made that support this? Explain.

Short answer

Intramolecular forces, such as covalent, ionic, and metallic bonds, are generally stronger than intermolecular forces, like hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Observations supporting this claim include the differences in boiling and melting points of substances with varying bond types and the fact that chemical reactions involve the breaking and rearrangement of intramolecular bonds, not intermolecular forces.

Step-by-step solution

Intermolecular vs Intramolecular forces

Intermolecular forces occur between molecules, while intramolecular forces occur within a molecule. Intermolecular forces include hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Intramolecular forces, on the other hand, involve chemical bonds, such as covalent, ionic, and metallic bonds.

Comparing the strength of Intermolecular and Intramolecular forces

Generally, intramolecular forces (chemical bonds) are stronger than intermolecular forces. This is because intramolecular forces involve the sharing or transfer of electrons between atoms within a molecule, leading to the formation of stable chemical bonds. Intermolecular forces, however, are weaker interactions that result from fluctuations in electron distribution around molecules and affect properties such as boiling and melting points, solubility, and viscosity.

Observation: Boiling and Melting points

One observation that supports this claim is the difference in boiling and melting points of substances with different types of intramolecular forces. For example, substances with strong covalent bonds, such as diamonds, have very high melting points compared to substances with weaker intermolecular forces, such as water. This indicates that the strength of intramolecular forces plays a significant role in determining the boiling and melting points of substances.

Observation: Chemical reactions

Another observation is during chemical reactions; only the intramolecular bonds are broken and rearranged to form new products. Intermolecular forces are not strong enough to cause such changes in the molecular structure. This observation also highlights that intramolecular forces are stronger than intermolecular forces. In conclusion, intramolecular forces are generally stronger than intermolecular forces. Observations such as differences in boiling and melting points, as well as the breaking and forming of chemical bonds during reactions, support this claim.