Nursing Entrance Exam

Page 169 © 2018 The liquid itself lacks the required heat energy to convert and escape as gas. With the application of heat, the liquid’s temperature rises and the water molecules on the surface turn to vapor, or gas, and evaporate from the liquid’s surface. Evaporation is different from boiling, which is another form of vaporization. Evaporation occurs only on the surface of the liquid, while boiling affects the entire body of liquid. With boiling, the temperature of the entire liquid rises and the liquid is converted to vapor by the heat. Evaporation is also an important part of life and the water cycle. The sun provides the solar energy needed for natural evaporation to take place as water evaporates from lakes, rivers, oceans, and soil moisture. For evaporation to occur, the surface of the liquid has to be exposed for heat to be applied to the surface of the liquid and for the molecules to be able to escape. With natural evaporation, heat from the sun heats the surfaces of water in oceans, rivers, soil, and other water bodies. The heated molecules will collide with each other and transfer some of the energy to each other in different degrees based on how the collision happened. When a molecule near the liquid’s surface acquires enough kinetic energy it would be able to turn to vapor and escape into the air. Water molecules that escape as vapor go up to the air where they form clouds. Evaporation depends on three main factors, which are atmospheric pressure as determined by the humidity percentage, heat, and air movement. Therefore, evaporation increases as temperature or wind conditions increase. It is also important to note that as the molecules escape with the heat and energy, the remaining water has reduced kinetic energy and temperature. Water temperature declines as evaporation occurs, also known as evaporation cooling. Vaporization Vaporization is a process in which a liquid is converted into a gas. Vaporization happens either by evaporation or boiling. Sublimation occurs when the transition from the liquid phase to the solid phase occurs without the gas phase. The word “vaporization” has also been used to describe the extensive destruction of physical objects exposed to intense heat, or the effect of nuclear weapons. For example, the bodies in Nagasaki and Hiroshima are described as having been vaporized after the 1945 atomic bombings. Condensation Condensation is the transition from a gaseous phase to a liquid phase. Condensation is the reverse of vaporization. If the transition is from a gas to a solid phase, without going through a liquid phase, it is called deposition. Condensation occurs when the temperature of the gas molecules drops or the molecules within the gas combine to form clusters. Condensation can also occur when gas molecules come in contact with a solid or liquid surface. Achieve

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