Why does an evaporating liquid cool down according to the Kinetic Molecular Theory? The highest velocity molecules are lost. Heat must be dissipated to break the liquid bonds. Heat is required to evaporate a liquid. Heat is lost through elastic collisions.

ccording to the Kinetic Molecular Theory, an evaporating liquid cools down because **the highest velocity molecules are lost**. <br /><br />When a liquid evaporates, the molecules with the highest kinetic energy (i.e., those moving the fastest) are the ones most likely to escape from the surface of the liquid into the gas phase. As these high-energy molecules leave, the average kinetic energy of the remaining molecules decreases, which results in a lower temperature for the liquid. This process is why evaporation has a cooling effect.<br /><br />So, the correct answer is:<br />- The highest velocity molecules are lost.