Why is evaporation endothermic

The gaseous molecules must release large amounts of kinetic energy to slow down enough to form the temporary bonds required to become a liquid.

The extra heat goes out of the system into the surrounding environment. In a solid particles have the lowest amount of energy relative to those in a liquid state and a gaseous state the highest amount of energy of the three states. Bonds require energy to break and release energy when being formed. To form a liquid from a solid, we need to break bonds and to form a gas from a liquid we need to break even more bonds. This requires a higher input of energy each time more bonds are broken.

Linking this to solid, liquid and gas states, when you vaporise a substance turn it into a gas you are promoting the particles in the substance to a state whereby they will possess more energy. This energy has to 'come' from somewhere and so energy is taken in from the surroundings of the process. With state changes, this is usually in the form of heat although pressure can be also be factored in.

Condensation is a gas turning into a liquid and so thus a high energy 'state' of particles becoming a lower energy 'state' of particles. If the overall energy of the particles involved is lower than before the process occurred, energy must have been released and thus the process can be considered exothermic. Why is vaporization endothermic? When water is heated, it evaporates.

The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor. Heat from the sun, or solar energy, powers the evaporation process. The opposite of evaporation is condensation. Condensation describes the phase change from gas to liquid. Evaporation occurs when molecules at the surface of a liquid enter the gas phase at a temperature below the boiling point of the substance. Examples of Evaporation. Two familiar examples of evaporation are sweating and the rain cycle.

Water on earth's surface evaporates and travels up through the atmosphere, where it's cooler. The cooler temperatures cause the vapor to condense back into water droplets, which come together to form clouds. Net evaporation occurs when the rate of evaporation exceeds the rate of condensation.

Separating solids from liquids — evaporation. Evaporation is used to separate a soluble solid from a liquid. For example, copper sulfate is soluble in water — its crystals dissolve in water to form copper sulfate solution. During evaporation , the water evaporates away leaving solid copper sulfate crystals behind. It turns out that all liquids can evaporate at room temperature and normal air pressure.

Evaporation happens when atoms or molecules escape from the liquid and turn into a vapor. Not all of the molecules in a liquid have the same energy. Evaporation rates , which are provided by meteorological stations, are found by measuring and recording water losses by evaporation over many years. Evaporation rates are usually expressed as the water depth lost in millimetres over a period of time, e. How is evaporation of water endothermic? Category: science chemistry. Evaporation is endothermic because water molecules must absorb heat from the surroundings to increase their kinetic energy.

One familiar example is sweat, which cools the human body as it evaporates from the skin. Is boiling exothermic? Is sweating endothermic or exothermic? When the kinetic energy of the molecules in a liquid become greater than the intermolecular attractions between them, evaporation occurs. The boiling point of a liquid is directly related to the vapor pressure of the liquid. Vapor pressure is a measure of the vapor present in a liquid.

When the vapor pressure equals the atmospheric pressure boiling occurs. It is important to remember that vaporization is an endothermic process as heat is removed from the liquid through boiling. The freezing and melting points of a liquid exist at the same temperature and represent an equilibrium between the liquid and solid phases.

The heating curve is a representation of the phases of a substance compared to the temperature and internal energy of a substance. The blue lines represent the different phases of a substance while the red lines represent the heats of fusion and vaporization. The phase diagram is another representation of the internal energy of a substance compared with the pressure and temperature of its surroundings.

Changes of State Objectives: 1. Compare the different states of matter in terms of potential and kinetic energy 3.