15. False. Condensation is the change of state from a gas to a liquid.
16. True. For a gas to become a liquid, large numbers of particles must clump together. Particles clump together when the attraction between them overcomes their kinetic energy. This attraction is known as intermolecular forces, which are responsible for holding particles together in a liquid state. As the temperature decreases, the kinetic energy of the particles decreases, and the intermolecular forces become stronger, causing the particles to come closer together and form a liquid.