Kinetic Molecular Theory Quiz

Kinetic Molecular Theory (KMT)

• KMT is a theory explaining molecular movement in different states of matter (solid, liquid, gas).
• Intermolecular forces are attractive forces between neighboring particles of one or more substances. These forces pull particles together.
• Kinetic energy keeps particles at a distance and/or moving. Kinetic energy depends on the substance's temperature.

States of Matter

• Solids: Particles are closely packed in a fixed arrangement.
• Liquids: Particles are closer than in a gas but can move past each other.
• Gases: Particles are widely dispersed and move freely.

Intermolecular Forces of Attraction

• Ionic Compounds: Intermolecular forces occur between oppositely charged particles (ions).
• Covalent Compounds: Attraction forces between neighboring molecules are weaker than those between formula units. This is because molecular attraction involves only partial charges.

Specific Intermolecular Forces

• London Dispersion Forces: Intermolecular forces of attraction existing between all atoms and molecules. These are the only forces acting in nonpolar molecules. They result from uneven electron distribution.
• Dipole-Dipole Forces: Exist between polar molecules. Polar molecules have unequal electron densities, creating a partial positive and a partial negative end (dipole). Attraction occurs between the positive end of one molecule and the negative end of another molecule. Repulsion occurs between like charges (positive and positive, or negative and negative).
• Hydrogen Bonds: A special type of dipole-dipole interaction. Exists in molecules with a hydrogen atom bonded to a small, highly electronegative atom (N, O, or F). Highly electronegative atoms strongly attract electrons, creating a highly polarized bond.
• Ion-Dipole Forces: Occur between an ion (either positive or negative) and a polar molecule. The ion is attracted to the oppositely charged end of the dipole. Cations are attracted to the partially negative end of a molecule, while anions are attracted to the partially positive end.