How to Calculate Saturation Vapor Pressure?

Joseph is an HVAC technician and a hobbyist blogger. He’s been working as an HVAC technician for almost 13 years, and he started blogging just...Read more

To calculate saturation vapor pressure, one must first understand the concept of partial pressure. Partial pressure is the pressure that each gas in a mixture would exert if it were present alone. In other words, it is the contribution that each gas makes to the total pressure.

To calculate the saturation vapor pressure of a given substance, one must know its boiling point. The higher the boiling point, the higher the saturation vapor pressure will be.

Saturated Vapor Pressure

  • The saturation vapor pressure is the maximum pressure that the water vapor can exert at a given temperature
  • The higher the temperature, the higher the saturation vapor pressure will be
  • To calculate the saturation vapor pressure, you will need to know the boiling point of water at your elevation
  • 1) Find the boiling point of water at your elevation
  • 2) Use this formula: 6
  • 11 * 10 ^ (7
  • 5 * T / (237 + T)) 3) T is the boiling point of water in Celsius 4) This formula will give you P, which is saturation vapor pressure in millibars

How to Calculate Saturation Vapor Pressure from Temperature

When it comes to calculating the saturation vapor pressure (SVP) from temperature, there are a few different methods that can be used. In this blog post, we will go over how to calculate SVP using the Antoine Equation and the Goff-Gratch Equation. The Antoine Equation is a widely used method for calculating SVP.

This equation takes into account the influence of temperature on vapor pressure. The general form of the Antoine Equation is: ln(Pₐ) = A – (B/(T+C))

where Pₐ is the saturation vapor pressure (in mmHg), T is the temperature (in °C), and A, B, and C are coefficients that vary depending on the substance being vaporized. These coefficients can be found in tables or online databases such as NIST Chemistry WebBook. Once you have determined the appropriate coefficients for your substance, plugging in your values for Pₐ and T will give you ln(Pₐ).

To solve for Pₐ, simply take the inverse natural logarithm of both sides of the equation. This will give you your answer in mmHg. The Goff-Gratch Equation is another way to determine SVP from temperature.

This equation was developed specifically for water vapor and gives more accurate results than the Antoine Equation when dealing with temperatures near 0°C. The general form of the Goff-Gratch Equation is: P = 611.21 * exp((1730–T)/(233 + T)) where P is saturation vapor pressure (in Pa), T is temperature (in °C), and 1730–T/(233 + T) is called ΔΤ .

If you want your answer in mmHg, simply multiply P by 760mmHg/101325Pa .

Saturated Vapor Pressure

Saturated Vapor Pressure – When a liquid is heated, its molecules gain energy and begin to move faster. As they move faster, they collide with other molecules more often. Eventually, the average kinetic energy of the molecules becomes equal to the average kinetic energy of the surrounding gas molecules.

At this point, the liquid is said to be at its saturated vapor pressure (SVP). The SVP is the pressure exerted by a saturated vapor in equilibrium with its non-vapor phase. If a container of water is sealed at room temperature, the water will evaporate until it reaches equilibrium with the surrounding air.

The partial pressure of water vapor in the air will be equal to the SVP of water at that temperature. The higher the temperature, the higher the SVP. For example, water boils at 100°C (212°F) because that is when its SVP equals atmospheric pressure (1 atmosphere = 14.7 psi).

When a liquid is cooled, its molecules slow down and collide less often. As a result, evaporation decreases and eventually stops when the partial pressure of vapor in equilibrium with its liquid phase becomes equal to atmospheric pressure; this happens when the liquid reaches its dew point Temperature/Pressure relationship for Water The table below shows how saturation vapor pressures increase with temperature for water:

As you can see from looking at this table, as temperatures increase so does saturated vapor pressure. This occurs because as particles are heated they gain more kinetic energy which makes them collide more frequently.

Saturation Vapor Pressure at 30 C

The air at 30 °C is 34.6 g/m³ and the saturated vapor pressure is 21.8 kPa. The temperature of the air (in Kelvin) is 303.15 K. The specific heat of dry air is 1.005 kJ/kg·K while the specific heat of water vapor is 2.01 kJ/kg·K. The latent heat of vaporization of water at 30 °C is 2,453 kJ/kg.

The saturation vapor pressure is the partial pressure exerted by water vapor in equilibrium with liquid water at a given temperature; that is, when there is no net evaporation or condensation taking place.[1] The higher the temperature, the greater the saturation vapor pressure.[2] For example, at 70 °F (21 °C), the saturation vapor pressure of water is 2469 Pa (0.3613 psi).[3][4]

At 0 °C, it drops to 611 Pa (0.0880 psi).[5] Saturation occurs when both liquid and gas phases are present in equilibrium; that is, when there isn’t any net transfer of mass between them.[6][7]

If additional water were added to a closed container filled with saturated air (i.e., if more water were evaporated), then some of that water would immediately condense on surfaces within the container until equilibrium was reached again.[8][9] Conversely, if liquid water were removed from such a system (i.e., through condensation), then some moisture would be drawn out of the air until equilibrium was restored.[10][11]

The temperature at which saturation occurs varies depending on both humidity and barometric pressure: warmer temperatures result in increased saturation vapour pressures,[12][13] while higher barometric pressures reduce them.[14][15][16].

How to Calculate Saturation Temperature

Saturation temperature is the temperature at which a substance changes from a liquid to a gas. The most common way to calculate this temperature is to use the Clausius-Clapeyron equation, which states that: T_s = T_0 \left( \frac{P}{P_0} \right)^{\frac{\Delta H}{R \Delta S}}

where: T_s is the saturation temperature (in Kelvin) T_0 is the standard temperature (in Kelvin)

P is the pressure of the substance (in Pascal)

Relationship between Saturation Vapor Pressure And Temperature

As the temperature increases, the saturation vapor pressure also increases. The relationship between these two variables can be represented by a line on a graph. The steeper the line, the greater the increase in vapor pressure with increasing temperature.

The slope of this line is known as the vapor pressure constant. It is a measure of how quickly the saturation vapor pressure changes with temperature. For example, at a given temperature, if the saturated vapor pressure is increased by 10%, then the constant would be 10%.

The relationship between saturation vapor pressure and temperature can be used to determine the dew point temperature. This is the temperature at which water droplets will begin to condense out of air that is cooled at a constant rate. To find the dew point, start with any temperatures above freezing and plot them on a graph along with their corresponding saturation vapor pressures.

Then, draw a horizontal line from left to right that intersects this curve at its lowest point. This point represents the dew point; any further cooling of air will cause water droplets to condense out of it.

How Do I Calculate Saturation?

To calculate saturation, you need to know the concentration of the solute in the solution and the solubility of the solute in the solvent. The saturation point is when the amount of solute in solution equals the maximum amount that can be dissolved (the solubility). At this point, adding more solute will not dissolve it; instead, it will precipitate out of solution.

The formula for calculating saturation is: [Solute] = [Solvent] * Solubility where [solute] is the concentration of the solute, [solvent] is the concentration of the solvent, and Solubility is the maximum amount of solute that can be dissolved per unit volume of solvent.

How Do You Calculate Vapor Pressure?

To calculate vapor pressure, you’ll need to know the temperature and the vaporization rate of the liquid. The vaporization rate is a measure of how quickly the liquid turns into a gas. To find the vaporization rate, you can use a tool like a thermometer or a hygrometer.

Once you have the vaporization rate and temperature, you can plug those numbers into the Clausius-Clapeyron equation. This equation will give you the vapor pressure of the liquid at that particular temperature.

How is Vapor Pressure Related to Saturation Pressure?

The saturation pressure is the pressure at which a given substance can first vaporize. The vapor pressure is the pressure of the vapor above its liquid state. The two are related in that the saturation pressure is dependent on the vapor pressure.

For example, water has a much higher vapor pressure than ice, meaning that it can exist in a gaseous state at lower temperatures than ice can. The relationship between saturation and vapor pressures can be represented by a phase diagram.

What is Saturation Water Vapor Pressure?

Saturation vapor pressure (SVP) is the maximum amount of water vapor that can be held in the air at a given temperature. The higher the temperature, the more water vapor that can be held in the air. When SVP is reached, any additional water vapor will condense out of the air.

The dew point is the temperature at which SVP is reached and condensation begins. The concept of saturation is important in many areas of atmospheric science, including cloud physics and precipitation forecasting. When air cools to its dew point or below, any excess water vapor will condense out to form clouds or precipitation.

This process releases latent heat, which can further impact weather patterns. For example, if enough latent heat is released during thunderstorm formation, it can create an updraft strong enough for the storm to become severe. Meteorologists use various models and instruments to measure or estimate SVP in order to forecast weather conditions.

One such model is the skew-T log-P diagram, which uses thermodynamic principles to plot data from weather balloons on a graph. This allows meteorologists to visualize how close air parcels are to saturation and identify potential areas of instability that could lead to severe weather.


The process of calculating saturation vapor pressure is not difficult, but it does require a few steps. First, you’ll need to gather the following information: the temperature of the air, the dew point temperature, and the barometric pressure. With this information in hand, you can use one of two formulas to calculate saturation vapor pressure.

The first formula is more accurate for temperatures above freezing, while the second is better for lower temperatures.

Joseph is an HVAC technician and a hobbyist blogger. He’s been working as an HVAC technician for almost 13 years, and he started blogging just a couple of years ago. Joseph loves to talk about HVAC devices, their uses, maintenance, installation, fixing, and different problems people face with their HVAC devices. He created Hvacbuster to share his knowledge and decade of experiences with people who don’t have any prior knowledge about these devices.

More Posts

Leave a Comment