Vapor Pressure of Water Calculator

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**Step 1 :**

**Step 2 :**

Vapor pressure is the minimum amount of pressure that must be applied to a liquid's surface to prevent it from evaporating. In other words it is an indication of a liquids evaporation rate.

**Vapor pressure of water (P) = 10**^{A−[B/(C+T)] }

Where

Where

**P**- Vapor Pressure of Water**T**- Water Temperature, in Celsius**A,B,C**- Antoine Constants for Water. When water temperature in the range of 1-100 Celsius A=8.07131, B=1730.63, C=233.426; when the temperature in the range of 99-374 degree Celsius, A=8.14019, B=1810.94 and C=244.485.

Read the problem and observe the value of water temperature given.

Substitute the value of temperature in the formula.

** P =10 ^{A−[B/(C+T)]}**

Calculate the vapor pressure of water at 70

^{o}F.**Step 1 :**The temperature of water is given as 70

^{o}F. Convert it into centigrade.

70

^{o}F = 21.1^{o}C**Step 2 :**Substitute the value in the formula to obtain the vapor pressure of water.

P = 10

^{A−[B/(C+T)]}

P = 10

^{8.07131 - [1730.63/(233.426+21.1)]}

P = 18.701 mmHg

**Answer :**The vapor pressure of water is P = 18.701 mmHg.

Calculate the vapor pressure of water at 65

^{o}F.**Step 1 :**The temperature of water is given as 65

^{o}F. Convert it into centigrade.

65

^{o}F = 18.3^{o}C**Step 2 :**Substitute the value in the formula to obtain the vapor pressure of water.

P = 10^{A−[B/(C+T)]}

P = 10^{8.07131 - [1730.63/(233.426+18.3)] }

P = 15.712 mmHg

**Answer :**The vapor pressure of water is P = 15.712 mmHg