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The terms sensible heat and latent heat refer to energy transferred between a body and its surroundings, defined by the occurrence or non-occurrence of temperature change; they depend on the properties of the body. Sensible heat is sensed or felt in a process as a change in the body's temperature.
Temperature-dependency of the heats of vaporization for water, methanol, benzene, and acetone. In thermodynamics, the enthalpy of vaporization (symbol ∆H vap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy that must be added to a liquid substance to transform a quantity of that substance into a gas.
If wet steam is heated further, the droplets evaporate, and at a high enough temperature (which depends on the pressure) all of the water evaporates, the system is in vapor–liquid equilibrium, [7] and it becomes saturated steam. Saturated steam is advantageous in heat transfer due to the high latent heat of vaporization.
If the latent heat is known, then knowledge of one point on the coexistence curve, for instance (1 bar, 373 K) for water, determines the rest of the curve. Conversely, the relationship between ln P {\displaystyle \ln P} and 1 / T {\displaystyle 1/T} is linear, and so linear regression is used to estimate the latent heat.
Heat capacity, c p: 0.212 J/(mol K) at −200°C Liquid properties Std enthalpy change of formation, Δ f H o liquid: −318.2 kJ/mol Standard molar entropy, S o liquid: 180 J/(mol K) Heat capacity, c p: 2.68 J/(gK) at 20°C-25°C Gas properties Std enthalpy change of formation, Δ f H o gas: −261.1 kJ/mol Standard molar entropy, S o gas: 333 ...
The liquid is then transformed into vapor which removes heat from the surface of the body. [46] The rate of evaporation heat loss is directly related to the vapor pressure at the skin surface and the amount of moisture present on the skin. [44] Therefore, the maximum of heat transfer will occur when the skin is completely wet.
Examples: heat of vaporization or heat of fusion). For hydrogen, the difference is much more significant as it includes the sensible heat of water vapor between 150 °C and 100 °C, the latent heat of condensation at 100 °C, and the sensible heat of the condensed water between 100 °C and 25 °C.
The table below gives thermodynamic data of liquid CO 2 in equilibrium with its vapor at various temperatures. Heat content data, heat of vaporization, and entropy values are relative to the liquid state at 0 °C temperature and 3483 kPa pressure. To convert heat values to joules per mole values, multiply by 44.095 g/mol.