As a liquid is heated, the average kinetic energy of its particles increases. The rate of evaporation increases as more and more molecules are able to escape the liquid’s surface into the vapor phase. Eventually a point is reached when the molecules all throughout the liquid have enough kinetic energy to vaporize . At this point the liquid begins to boil. The boiling point is the temperature at which the vapor pressure of a liquid is equal to the external pressure. The Figure below illustrates the boiling of liquid.
Sarah is cooking dinner for her husband's parents and puts two pots of water on the stove to boil. She turns the heat on pot A to high, but forgets to turn on the heat for pot B. Eventually, pot A begins to boil but pot B is still room-temperature.
Is the rate of evaporation lower in pot A or pot B?