why should the vapour pressure equal to the atmospheric pressure?

. In such a state, although the amount of liquid level in the vessel does not change, evaporation has not stopped and the system is not at rest. In fact, the number of molecules, which escape from the liquid to the gaseous phase (due to evaporation), becomes equal to the number of va..

Vapour Pressure of Liquids - Vapour pressure is defined as the partial pressure exerted by the vapors above the liquid surface in equilibrium with liquid at a given temperature. fig 3.3 In illustrations 1a and 1b, the liquid and vapor states of a gi..

Atmospheric pressure is measured by an instrument known as barometer. This consists of a glass tube closed at one end and filled with pure mercury. The tube is then inverted into an open vessel of mercury. The mercury level in the tube drops until the pressure due to ..

The maximum height of mercury, which can be supported by the atmospheric pressure provides a measure of that pressure. A standard pressure of one atmosphere (1 atm) is defined as the pressure that will support a column of mercury of 76 cm..

Atmospheric Pressure - The atmosphere is the layer of air around the earth. It extends up to 1000 km above the surface of the earth and has a total weight of 4.5 10 1 8 kg (i.e., five million billion tons). This weight exerts a pressure on the surface of the ..

The gaseous envelope surrounding the Earth is called earth's atmosphere, extending to a few kilometres above the surface. The pressure exerted by the atmosphere is called atmospheric pressure. The magnitude of this pressure is nearly 1.01..

Some chemical reactions need very high pressure to proceed. For e.g., in the manufacture of ammonia from nitrogen and hydrogen (Haber's process), a pressure of over 200 atmosphere is required, in presence of a catalyst iron and a temperature of 450 o C to 500 o ..

SI unit of pressure is N/m 2 or Pascal (Pa) Atmospheric pressure is also expressed in mm of Hg or cm of Hg. Another unit is torr. [1 torr= 1mm of Hg] For meteorological purposes, the unit used is bar...

In 1886 the French chemist Francois Marie Raoult carried out a series of experiments to study the vapor pressure of a number of binary solutions containing non-volatile as well as volatile non electrolyte solutes. On the basis of the results of the experiment he stated a law known as Raou..