The molecules gain energy so they break up the solid structure and move more freely, however, they still have some attraction. More energy is required to weaken this attraction This molecule to molecule attraction is weakest in gaseous state of matter
Velocity of molecular movement is lower in larger molecules because it takes more energy to get the larger molecule moving. On the other hand, smaller molecules move more rapidly causing its velocity to be higher.
In a transverse wave, a molecule/particle will move up and down, with double the amplitude of the wave. In a longitudinal wave, the molecule/particle will move side to side, equal to the wavelength (?) of the wave
They have more kinetic energy so they have a higher temperature, assuming the liquid and solid molecules are the same molecule. When you heat up something solid (like ice), you add energy, and the molecules move more quickly and separate, turning into a liquid (like water) and then a gas.