strong force

Examples of strong force in the following topics:

• Nuclear Fission

  • The strong nuclear force is the force between two or more nucleons.
  • These two forces produce opposite effects in the nucleus.
  • The strong nuclear force acts to hold all the protons and neutrons close together, while the electromagnetic force acts to push protons further apart.
  • In atoms with small nuclei, the strong nuclear force overpowers the electromagnetic force.
  • As the nucleus gets bigger, the electromagnetic force becomes greater than the strong nuclear force.

• Nuclear Binding Energy and Mass Defect

  • The rationale for this peak in binding energy is the interplay between the coulombic repulsion of the protons in the nucleus, because like charges repel each other, and the strong nuclear force, or strong force.
  • The strong force is what holds protons and neutrons together at short distances.
  • As the size of the nucleus increases, the strong nuclear force is only felt between nucleons that are close together, while the coulombic repulsion continues to be felt throughout the nucleus; this leads to instability and hence the radioactivity and fissile nature of the heavier elements.

• Nuclear Fusion

  • The origin of the energy released in fusion of light elements is due to an interplay of two opposing forces: the nuclear force that draws together protons and neutrons, and the Coulomb force that causes protons to repel each other.
  • This force, called the strong nuclear force, overcomes electric repulsion in a very close range.
  • The effect of nuclear force is not observed outside the nucleus, hence the force has a strong dependence on distance; it a short-range force.
  • At nucleus radii distances, the attractive nuclear force is stronger than the repulsive electrostatic force.
  • Describe the electrostatic and strong nuclear forces and how they act to oppose or promote a fusion reaction

• Hydrogen Bonding

  • A hydrogen bond is a strong intermolecular force created by the relative positivity of hydrogen atoms.
  • A hydrogen bond results when this strong partial positive charge attracts a lone pair of electrons on another atom, which becomes the hydrogen bond acceptor.
  • The hydrogen bonds formed between water molecules in water droplets are stronger than the other intermolecular forces between the water molecules and the leaf, contributing to high surface tension and distinct water droplets.

• Capillary Action

  • The molecules in any sample of matter experience intermolecular forces, which are attractive or repulsive forces between atoms or molecules within the sample.
  • These cohesive forces are especially strong at the surface of a liquid, resulting in the phenomenon of surface tension.
  • It occurs when the intermolecular attractive forces between the liquid and the solid surrounding surfaces (adhesive forces) are stronger than the cohesive forces within the liquid.
  • Adhesion forces between the fluid and the solid inner wall pull the liquid column up until there is a sufficient mass of liquid for gravitational forces to counteract these forces.
  • The curvature of the surface at the top of a column of fluid in a narrow tube is caused by the relative strength of the forces responsible for the surface tension of the fluid (cohesive forces) and the adhesive forces to the walls of the container.

• Introduction to Bonding

  • These bonds include both strong intramolecular interactions, such as covalent and ionic bonds.
  • They are related to weaker intermolecular forces, such as dipole-dipole interactions, the London dispersion forces, and hydrogen bonding.
  • The weaker forces will be discussed in a later concept.
  • Chemical bonds are the forces of attraction that tie atoms together.
  • Ionic compounds, though composed of strong bonding interactions, tend to form brittle crystalline lattices.

• Hydrogen Bonding

  • The most powerful intermolecular force influencing neutral (uncharged) molecules is the hydrogen bond.
  • The exceptionally strong dipole-dipole attractions that cause this behavior are called the hydrogen bond.
  • Coulombic forces are inversely proportional to the sixth power of the distance between dipoles, making these interactions relatively strong, although they are still weak (ca. 4 to 5 kcal per mole) compared with most covalent bonds.
  • The unique properties of water are largely due to the strong hydrogen bonding that occurs between its molecules.

• Steric Effects

  • When two neutral atoms (A & B) are close enough to detect each other, they experience an attraction due to dispersion forces.
  • Consequently, as the two atoms come together, an initial attraction becomes a strong repulsion, as shown by the dark blue curve.

• Physical Properties of Carboxylic Acids

  • This reflects differences in intermolecular attractive forces in the crystalline state.
  • Again, changes in crystal packing and intermolecular forces are responsible.
  • In general, dipolar attractive forces between molecules act to increase the boiling point of a given compound, with hydrogen bonds being an extreme example.
  • The high boiling points of the amides and nitriles are due in large part to strong dipole attractions, supplemented in some cases by hydrogen bonding.

• Intermolecular Forces and Solutions

  • The strength of the intermolecular forces between solutes and solvents determines the solubility of a given solute in a given solvent.
  • There are two conceptual steps to form a solution, each corresponding to one of the two opposing forces that dictate solubility.
  • Many intermolecular forces can contribute to solvation, including hydrogen bonding, dipole-dipole forces, and Van Der Waals forces.
  • Another common example of these forces at work is an ion-dipole interaction, which arises when water solvates ions in solution.
  • This interaction arises most prevalently when strong or weak electrolytes are place in water.