Vapour pressure is the pressure of the steam of a substance at a certain temperature.
This does not automatically mean that the substance is completely evaporated. When the vapour pressure reaches the surrounding (atmospheric) pressure, the substance starts to boil or sublimate.
Also at very low temperatures, even when the substance is in solid state, a certain amount of substance already exists as vapour. Though, for the most substances, the proportion of vapour is very small compared to the solid portion.
Finally, a substance does not have to melt before it evaporates. This is called sublimation and occurs, e.g., when solid carbon dioxide (dry ice) is used: It will evaporate directly from the solid state (under normal ambient physical conditions), because, with rising temperature, the vapour pressure is already exceeding the atmospheric pressure before the melting point is reached.
For details, have a look at the provided link.
evaporation as such influence on the total pressure. evaporation occurs when the total pressure is greater than the surface molecules vapour pressure. as the rate of evaporation increases , more vapour will be there at the top, and then the new total pressure will become the sum of the earlier total pressure and vapour pressure of the vapour evaporated. hence total pressure increases.............
Equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) in a closed system at a specific temperature. It represents the balance between molecules escaping from the condensed phase and re-entering it.
Alcohol typically has a higher vapor pressure than water at a given temperature due to its lower molecular weight and weaker intermolecular forces. This means that alcohol evaporates more readily than water.
Relative lowering of vapour pressure is function of pressure of pure liquid and pressure of solutions when you increase temperature both the values increase and compensate the increase value, According to the Raoult's law, Psolvent = Xsolvent Po where Psolvent is the vapour pressure of the liquid solution, Xsolvent is its mole fraction in the solution and Po is the pure vapour pressure.
Relative lowering of vapour pressure is function of pressure of pure liquid and pressure of solutions when you increase temperature both the values increase and compensate the increase value, According to the Raoult's law, Psolvent = Xsolvent Po where Psolvent is the vapour pressure of the liquid solution, Xsolvent is its mole fraction in the solution and Po is the pure vapour pressure.
Actual vapor pressure can be calculated using the Antoine equation, which is a function of temperature and constants specific to the substance of interest. The equation is: ln(P) = A - (B / (T + C)), where P is the actual vapor pressure, T is the temperature in Kelvin, and A, B, and C are substance-specific constants.
The partial pressure of water (vapor) is included in the total pressure of the atmosphere (air) when boiling.
boiling
Both will have same vapour pressure as salt{NACL} would get trapped in ice and in solid iced state get seprated from pure ice crystals. so in case melting of ice in soln state pure water will have more vapour pressure but in solid state both will have same vapour pressure.
Yes, vapor pressure is an intensive property because it does not depend on the amount of substance present. It is characteristic of the specific substance at a given temperature and does not change with the quantity of the substance.
Relative humidity (RH) is the ratio of the partial pressure of water vapour to the saturation vapour pressure of water at the same temperature. Relative humidity depends on temperature and the pressure. Very roughly speaking, it is a ratio of the amount of water vapour in the air compared to the total amount of water vapour that it possible for that air to contain.
When this liquid has a great vapour pressure.