Answer: The “latent heat of evaporation” is the heat required to change a liquid into a vapor. “Latent”, by definition, means; hidden, not seen or apparent, dormant. When a liquid evaporates it uses the heat of the liquid, to change state into a vapor. That is why when a breeze passes over our sweaty arm or face we suddenly feel cooler. That is because the heat of our skin transformed the sweat into water vapor taking heat away from our body. This is called adiabatic cooling since the system is closed and changes in the state of the water are affected without loss or gain of heat. The heat is now locked in the air as humidity (water vapor) without changing the temperature of the air. When the the heat is released, (like when the humid air touches a cold air mass) the water vapor condenses back into a liquid.
If we boil water at sea level air pressure, the water will increase temperature until it becomes 210 degrees F. Then, no matter how much heat we add to the water, the water will remain at 210 degrees. However, the water will begin to boil away. The temperature of the water vapor (steam) is also 210 degrees. Yet, we are adding heat to the water. The more heat we add to the water, the more steam we will produce. Therefore that added heat is “hidden” as latent heat in the water vapor we have produced.
Step-by-step explanation: