Search results
Results from the WOW.Com Content Network
Adhesion – the attraction of molecules or compounds for other molecules of a different kind; Specific heat capacity – the amount of heat needed to raise the temperature of one gram of a substance by one degree Celsius; Heat of vaporization – the amount of energy needed to change one gram of a liquid substance to a gas at constant temperature
2 O; one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. [26] Water is a tasteless, odorless liquid at ambient temperature and pressure. Liquid water has weak absorption bands at wavelengths of around 750 nm which cause it to appear to have a blue color. [4]
A typical phase diagram.The solid green line applies to most substances; the dashed green line gives the anomalous behavior of water. In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. [1]
The pressure on a pressure-temperature diagram (such as the water phase diagram shown above) is the partial pressure of the substance in question. A phase diagram in physical chemistry , engineering , mineralogy , and materials science is a type of chart used to show conditions (pressure, temperature, etc.) at which thermodynamically distinct ...
P v ° is the standard vapor pressure for that liquid at that temperature and pressure. V is the molar volume. R is the gas constant; r k is the Kelvin radius, the radius of the droplets. The effect explains supersaturation of vapors. In the absence of nucleation sites, tiny droplets must form before they can evolve into larger droplets.
If the piston is slowly lowered, the system will trace a curve of increasing temperature and pressure within the gas region of the phase diagram. At the point where gas begins to condense to liquid, the direction of the temperature and pressure curve will abruptly change to trace along the phase line until all of the water has condensed.
During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure. This can be a discontinuous change; for example, a liquid may become gas upon heating to its boiling point, resulting in an abrupt change in volume. The identification of the ...
Cohesion causes water to form drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place. Water droplets are flatter on a Hibiscus flower which shows better adhesion. In surface science, the term adhesion almost always refers to dispersive adhesion.