The enthalpy of vaporization is the energy, in the form of heat, that a substance needs to change from a liquid to a gas at a constant temperature and pressure. Enthalpy of vaporization, designated as "delta H vap," is m... More » Science Biology

Delta H denotes the change in enthalpy, or energy, between products and reactants in chemical reactions. The change in enthalpy across a chemical reaction is the standard enthalpy of formation of the products minus the s... More » Science Physics

Table salt, which is sodium chloride, is an ionic compound. The attractive forces between the positive and negative ions in ionic compounds are strong and require a large amounts of energy to break. This means that a hig... More » Food Food Facts Herbs & Spices
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The heat of vaporization is the amount of energy that is required to convert a substance from liquid to gaseous state without changing its temperature. A substance with a high heat of evaporation takes longer to transfor... More » Science Chemistry States of Matter

The enthalpy of formation is defined as the energy, in the form of heat, given off or absorbed during a chemical reaction under the most stable conditions for the reaction to occur from pure elements. The basic formula f... More » Science Chemistry

Diffusion is caused when heat in a gas or water environment creates energy that is absorbed by particles, making them move. This is referred to as thermal motion. Each particle moves in a different direction, but the dir... More » Science Biology

The energy required to change the temperature of a substance with no phase change is known as sensible heat. The change in temperature may come from the sun via the soil or the air. More » Science Physics Thermodynamics