latent
Definition
In science, latent heat is the heat that is absorbed or released by a substance during a change of state, such as melting or freezing. Latent heat is not visible, but it can be measured.
The amount of latent heat that is absorbed or released depends on the substance and the change of state. For example, the latent heat of fusion for water is 80 calories per gram. This means that it takes 80 calories of heat to melt 1 gram of ice.
Latent heat is important in many processes, such as cooking, air conditioning, and the hydrologic cycle. For example, latent heat is released when water vapour condenses to form clouds. This latent heat helps to drive the water cycle and create precipitation.
How can the word be used?
The latent heat of water is the energy that is released when water changes from a liquid to a gas.
Different forms of the word
Adjective: Latent is an adjective that describes something that is present but not visible or active. For example, latent heat is heat that is stored in a substance but is not released until the substance is changed in some way.
Noun: Latent is also used as a noun to refer to the potential for something to develop or become active. For example, a latent talent is a talent that is not yet developed but has the potential to be developed.
Verb: To latentize is to make something latent. For example, to latentize a disease is to cause it to become inactive but still present.
Etymology
The word "latent" comes from the Latin word "latēns", which means "hidden" or "lying in wait". It was first used in English in the 16th century.
The Latin word "latēns" is related to the Greek word "λάθρα" (lathra), which also means "hidden".
Question
What is latent heat?
AQA Science Exam Question and Answer
Question:
Explain the concept of latent heat and its significance in the phase transition of substances. Provide examples of how latent heat influences changes between solid, liquid, and gaseous states.
Answer:
Latent heat is a fundamental concept in thermodynamics that refers to the heat energy absorbed or released during a phase transition of a substance without causing a change in temperature. This heat energy is used to alter the internal arrangement of particles within the substance, either breaking or forming intermolecular bonds.
During the transition between solid to liquid states (melting) or liquid to gas states (vaporisation), heat energy is absorbed by the substance, causing its particles to overcome intermolecular forces and increase their kinetic energy. This energy is required to weaken the bonds holding the particles together and allows them to move more freely, resulting in a change of state.
Conversely, when transitioning from gas to liquid (condensation) or liquid to solid (freezing) states, heat energy is released as the particles lose kinetic energy. This energy is used to reestablish intermolecular bonds and reduce the particles' movement, leading to a phase change.
An example of latent heat in action is water boiling. As water transitions from liquid to gas (steam) at its boiling point, it absorbs latent heat. This heat energy breaks the hydrogen bonds between water molecules and converts them into water vapour, while the temperature remains constant.
In summary, latent heat is the energy absorbed or released during phase transitions without causing a temperature change. It is vital in understanding how substances transition between solid, liquid, and gaseous states, shaping various natural processes like evaporation, condensation, and melting.