Vapor Pressure Calculator is an online tool ,is used to analyse the Vapor pressure of the solids and liquids fastly. To get Vapor pressure of a solution as output, by using the equation Clausius-Clapeyron equation at given temperature or by using Raoult’s law,Simply need to give their details in all input fields and press the calculate button, to avail the result.
Vapor Pressure Calculator: To determine the Vapor pressure of the solids and liquids, we can use this tool Vapor pressure calculator.this calculator helps to you know the Vapor pressure of a solution at a given temperature using the Clausius-Clapeyron equation or Raoult’s law, to know about how does a liquid or solid changes in to gas due to change in pressure and temperature. Here we will explain what is meant by Vapor pressure,its formula, step by step procedure for how to use a Vapor pressure calculator. Also we have solved and explained a few problems in a step by step process for better understanding. At the end of the article we can find frequently asked questions with solutions.
The liquid eVaporates, the gaseous molecules formed will escape in the air. But, if the liquid is kept in a closed container, the gaseous molecules will not escape in the air but will remain above the liquid. Those eVaporated particles will create a pressure above the liquid, which is then known as the Vapor pressure.units of the Vapor pressure is the torr. 1 torr =1 mm Hg.
There are two Simple ways to find the Vapor pressure, that is the Clausius-Clapeyron equation and Raoult’s law.
Clausius-Clapeyron Equation:The Clausius-Clapeyron equation is used to find the Vapor pressure at any other temperature if the Vapor pressure, the enthalpy of Vaporization are known. If the temperature increases, then the Vapor pressure increases steadily. The Clapeyron equation is dP/dT = H / (T * ΔV)
The Clausius-Clapeyron equation describes the relation between the Vapor pressure and the liquid temperature. The phase transition between the liquid and gas is Vaporization or between solid and gas is the sublimation. If there is a big difference between the specific volume of the molecule gas phase and the condensed phase, then we use the following formula. ln(P₁/P₂) = ΔH/R * (1/T₂ - 1/T₁)
A solution is created when a solid gets dissolved into the liquid. The Vapor pressure formed from this solution is lowered by the addition of the solute. Here comes the Vapor pressure formula using Raoult’s law,.normal atmospheric pressure is 1 atm (760 mmHg or 101.325 kPa).
Psolution = (Xsolvent )( Po solvent )
Procedure to calculate Vapor pressure of a solution by using the equation Clausius - Clapeyron equation is explained as follows.
Procedure to calculate Vapor pressure of a solution with Raoult’s law, is as follows
Example 1.: The Vapor pressure of an aqueous solution is found to be 23.80 mmHg at 25 °C. What is the mole fraction of solute in this solution? The Vapor pressure of water is 25.756 mm Hg at 25 °C ?
Vapor pressure of the solution P solution = 23.80mmHg
Vapor pressure of the solvent P°solvent = 25.756 mm Hg
By using roult’s law formula
23.80 = X solvent * 25.756
X solvent = 0.92405
X solvent + X solute = 1
X solute = 1- X solvent
= 1 - 0.92405 = 0.07595
The mole fraction of the solute in the solution is 0.07595
Example 2.: The Vapor pressure of an aqueous solution is found to be 23.80 mmHg at 25 °C. What is the mole fraction of solute in this solution? The Vapor pressure of water is 25.756 mm Hg at 25 °C ?
Heat of Vaporization of 1-propanol = 47.2 kJ/mol
Initial pressure = 20 torr
Initial temperature = 14.7°C
Final temperature = 52.8°C
Convert °C to K
TK = °C + 273.15
T1 = 14.7 °C + 273.15
T1 = 287.85 K
T2 = 52.8 °C + 273.15
T2 = 325.95 K
Clausius-Clapeyron equation is ln(P₁/P₂) = ΔH/R * (1/T₂ - 1/T₁)
ln(20/P₂) = (47.2/0.008314) [1/325.95 - 1/287.85]
ln(20/P₂) = 5677(-4.06 x 10-4) = -2.305
P₂/20 = 10.02
P₂ = 200.4
Therefore, the Vapor pressure of 1-propanol at 52.8°C is 200.4 torr
1. What is meant by Vapor pressure?
Vapor pressure is a measure of the tendency of a material to change into a gases state or Vapor state and its increases with temperature.
2. What are the factors affecting the Vapor Pressure?
There are three common factors that influence the Vapor pressure are surface area, intermolecular force and temperature. The Vapor pressure of a molecule is differ at different temperatures.
3. What are the Units of Vapor Pressure?
Vapor pressure is measured in units of atmospheres(atm),millimetres of mercury(mmHg) or kilopascals(KPa).
4. Which instrument is used to measure Vapor pressure?
A manometer( U shaped glass tube with marks in the background) is a pressure measuring instrument.usually limited to measuring pressures near to the atmosphere.
5. What are the characteristics of Vapor pressure?
The important characteristics of Vapor pressure are given below,
6. What is the formula for Vapor pressure?
To find Vapor pressure we can use two equations in chemistry, The Clausius-Clapeyron equation gives the Vapor pressure at a temperature i.e ln(P₁/P₂) = ΔH/R * (1/T₂ - 1/T₁). Second one is Raoult's law i.e Psolution = Psolvent * Xsolvent.