pressure

In the realm of chemical reactions, the concept of pressure in dynamic equilibrium is a crucial aspect that governs the behavior of reactants and products. At dynamic equilibrium, the concentrations of reactants and products remain constant, and the forward and reverse reactions occur at equal rates. This state is characterized by the equilibrium constant (K), which is a measure of the ratio of products to reactants at equilibrium and has no units. The value of K is constant for a given reaction at a particular temperature and does not depend on the initial concentrations of reactants and products.

Understanding Equilibrium Constant (K)

The equilibrium constant (K) is a quantitative measure of the extent of a reaction at equilibrium. It is defined as the ratio of the concentrations of the products raised to their stoichiometric coefficients to the concentrations of the reactants raised to their stoichiometric coefficients. The general expression for the equilibrium constant (Kc) is:

Kc = [C]c × [D]d / [A]a × [B]b

Where:
– [C] and [D] are the equilibrium concentrations of the products
– [A] and [B] are the equilibrium concentrations of the reactants
– a, b, c, and d are the stoichiometric coefficients of the respective species

For example, consider the reversible reaction:

H2(g) + I2(g) ↔ 2HI(g)

At equilibrium, the concentrations of H2, I2, and HI are measured, and the equilibrium constant (Kc) is calculated using the formula:

Kc = [HI]2 / ([H2] × [I2])

For this reaction, the equilibrium constant (Kc) is 50.3 at 400 °C. This means that at equilibrium, the concentration of HI is 0.156 M, while the concentrations of H2 and I2 are 0.022 M each.

Factors Affecting Equilibrium

The concentrations of reactants and products in a reaction at dynamic equilibrium can be affected by changes in concentration, pressure, or temperature. According to Le Châtelier’s principle, if a system at equilibrium is subjected to a stress (such as a change in concentration or pressure), the system will adjust to relieve the stress and reach a new equilibrium.

Effect of Concentration Changes

• If the concentration of a reactant is increased, the system will shift to consume more of that reactant and produce more products, increasing the product concentrations.
• If the concentration of a product is increased, the system will shift to consume more of the product and produce more reactants, decreasing the product concentrations.

Effect of Pressure Changes

• In reactions involving gases, an increase in pressure will favor the side of the reaction with fewer moles of gas, as this will decrease the total volume and satisfy the pressure increase.
• Conversely, a decrease in pressure will favor the side of the reaction with more moles of gas.

Effect of Temperature Changes

• An increase in temperature will favor the endothermic (heat-absorbing) direction of the reaction, as this will increase the product concentrations.
• A decrease in temperature will favor the exothermic (heat-releasing) direction of the reaction, as this will increase the reactant concentrations.

Equilibrium Constant in Terms of Partial Pressures (Kp)

In the case of gases, concentration is often measured as partial pressure. The equilibrium constant for a reaction involving gases can be expressed in terms of partial pressures (Kp) instead of concentrations (Kc). The relationship between Kc and Kp is given by the formula:

Kp = Kc(RTΔn)Δngas

Where:
– R is the gas constant
– T is the temperature in Kelvin
– Δn is the change in the number of moles of gas in the reaction
– Δngas is the change in the number of moles of gas in the equilibrium constant expression

For example, consider the reaction:

N2(g) + 3H2(g) ↔ 2NH3(g)

The equilibrium constant (Kp) for this reaction is given by:

Kp = PNH32 / (PN2 × PH23)

Where P is the partial pressure of each gas.

Numerical Examples and Problems

1. Example 1: Consider the reversible reaction:
   H2(g) + I2(g) ↔ 2HI(g)
   At 400 °C, the equilibrium constant (Kc) is 50.3. If the initial concentrations of H2 and I2 are both 0.10 M, calculate the equilibrium concentrations of H2, I2, and HI.

Solution:
Let the equilibrium concentrations of H2, I2, and HI be x, x, and 2x, respectively.
Kc = [HI]2 / ([H2] × [I2])
50.3 = (2x)2 / (x × x)
50.3 = 4×2 / x2
x = 0.022 M
Therefore, the equilibrium concentrations are:
[H2] = [I2] = 0.022 M
[HI] = 2 × 0.022 = 0.044 M

1. Example 2: Consider the reaction:
   N2(g) + 3H2(g) ↔ 2NH3(g)
   At a certain temperature, the equilibrium constant (Kp) is 1.7 × 10^5. If the partial pressures of N2 and H2 at equilibrium are 0.80 atm and 0.60 atm, respectively, calculate the partial pressure of NH3 at equilibrium.

Solution:
Kp = PNH32 / (PN2 × PH23)
1.7 × 10^5 = PNH32 / (0.80 × 0.60^3)
PNH3 = √(1.7 × 10^5 × 0.80 × 0.60^3) = 13.2 atm

1. Problem: Consider the reaction:
   2SO2(g) + O2(g) ↔ 2SO3(g)
   At a certain temperature, the equilibrium constant (Kp) is 42.0. If the partial pressures of SO2 and O2 at equilibrium are 0.40 atm and 0.20 atm, respectively, calculate the partial pressure of SO3 at equilibrium.

Solution:
Kp = PSO32 / (PSO2^2 × PO2)
42.0 = PSO32 / (0.40^2 × 0.20)
PSO3 = √(42.0 × 0.40^2 × 0.20) = 0.80 atm

Graphical Representation of Equilibrium

The relationship between the concentrations or partial pressures of reactants and products at equilibrium can be represented graphically. The graph typically shows the changes in concentrations or partial pressures as a function of time until the system reaches equilibrium.

In the graph, the concentrations or partial pressures of the reactants and products are plotted against time. The system initially starts with the reactants, and as the reaction progresses, the concentrations of the products increase while the concentrations of the reactants decrease. Eventually, the system reaches a state of dynamic equilibrium, where the concentrations of the reactants and products remain constant over time.

Conclusion

The concept of pressure in dynamic equilibrium is a fundamental aspect of chemical reactions. Understanding the equilibrium constant (K), the factors affecting equilibrium, and the relationship between Kc and Kp is crucial for analyzing and predicting the behavior of chemical systems at equilibrium. The numerical examples and problems provided in this guide offer a comprehensive understanding of the practical applications of pressure in dynamic equilibrium.

Reference:

• Equilibrium Constant and Le Châtelier’s Principle
• Partial Pressures and the Equilibrium Constant
• Le Châtelier’s Principle

The melting point and pressure of a substance are two closely interrelated physical properties that play a crucial role in understanding the behavior and characteristics of materials. This comprehensive guide delves into the intricate details of the melting point-pressure relationship, providing a wealth of information for physics students and researchers.

Understanding the Melting Point-Pressure Relationship

The melting point of a substance is the temperature at which the solid phase transitions into the liquid phase. However, this transition is not solely dependent on temperature; pressure also plays a significant role in determining the melting point of a substance.

According to the ScienceDirect Topics article, the melting pressure relation is non-linear and multi-valued, meaning that a single pressure can correspond to two different temperatures. This highlights the importance of knowing the precise pressure at which the melting point is measured, as it can significantly affect the temperature at which the substance melts.

Performing Melting Point Analysis

The Chemistry LibreTexts article provides a detailed explanation of the melting point analysis process, emphasizing the importance of controlling the pressure during the analysis. The article states that the melting point is dependent on pressure, and experimental results can vary from literature values, especially in extreme locations, such as high-altitude environments.

The Westlab Canada article further emphasizes the importance of accurate and precise melting point determination, as it can provide valuable information about the purity and identity of a substance. Impurities and other factors, such as pressure and humidity, can affect the melting point of a substance, underscoring the need to control these variables during the analysis.

Quantifiable Data and Relationships

The ScienceDirect Topics article presents a graph showing the melting pressure relation for various substances, which can be used to determine the pressure at which a substance will melt at a given temperature. Additionally, the Chemistry LibreTexts article provides a table showcasing the melting point ranges for different substances, which can be utilized to assess the purity of a sample based on its melting point range.

Theorem and Formulas

Theorem:
The melting point of a substance is affected by pressure, as demonstrated by the non-linear and multi-valued melting pressure relation.

Physics Formula:
The relationship between melting point and pressure is described by the Clausius-Clapeyron equation:

ln(P2/P1) = -ΔHm/R * (1/T2 – 1/T1)

Where:
– P1 and P2 are the pressures at which the substance melts at temperatures T1 and T2, respectively.
– ΔHm is the enthalpy of fusion.
– R is the gas constant.

Physics Examples

1. A sample of a substance is heated at a constant pressure of 1 atm. The melting point of the substance is 100°C. If the pressure is increased to 2 atm, what is the new melting point of the substance?

2. A sample of a substance has a melting point range of 100-102°C at a pressure of 1 atm. If the pressure is decreased to 0.5 atm, what is the new melting point range of the substance?

Physics Numerical Problems

1. Given the following data for a substance:
2. ΔHm = 10 kJ/mol
3. R = 8.314 J/(mol·K)
4. P1 = 1 atm
5. T1 = 273 K
6. P2 = 2 atm

Calculate the new melting point of the substance at P2 using the Clausius-Clapeyron equation.

1. Given the following data for a substance:
2. ΔHm = 10 kJ/mol
3. R = 8.314 J/(mol·K)
4. P1 = 1 atm
5. T1 = 273 K
6. P2 = 0.5 atm

Calculate the new melting point range of the substance at P2 using the Clausius-Clapeyron equation.

Figures

Figure 1: Melting pressure relation for various substances
Figure 2: Melting point range of various substances

Data Points, Values, and Measurements

• Melting point ranges for various substances
• Melting pressure relation for various substances
• Enthalpy of fusion for various substances
• Gas constant

References

1. Melting Pressure – an overview | ScienceDirect Topics
   https://www.sciencedirect.com/topics/chemistry/melting-pressure
2. Quantitative structure‐property relationships for prediction of boiling points, vapor pressures, and melting points
   https://setac.onlinelibrary.wiley.com/doi/full/10.1897/01-363
3. 2.1: Melting Point Analysis – Chemistry LibreTexts
   https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Physical_Methods_in_Chemistry_and_Nano_Science_%28Barron%29/02:_Physical_and_Thermal_Analysis/2.01:_Melting_Point_Analysis
4. Measuring the Melting Point – Westlab Canada
   https://www.westlab.com/blog/measuring-melting-point
5. Melting point determination
   https://www.chem.ucalgary.ca/courses/353/laboratory/meltingpoint.pdf

In this article we shall discuss about osmotic pressure example. Osmosis refers to the movement of molecules from an area of higher concentration to lower concentration.

The movement takes place through a semi permeable membrane. This membrane divides the areas of higher concentration and lower concentration. In this article we shall discuss about notable features of osmosis and then discuss about osmotic pressure and its examples.

• Transportation of nutrients in trees
• Perspiration
• Absorption of nutrients from soil
• Absorption of water in resin
• Oxygen transfer to blood
• Potato in sugar solution
• Fish absorb water through skin and gills
• Red blood cells placed in freshwater
• Sugar on strawberries
• Food on preservation
• Absorption of digestive food in large and small intestines-
• Contact lens-induced dry eye
• Water purification

What is osmosis?

Osmosis refers to transfer of molecules through a semi permeable membrane from an area of higher concentration to an area of lower concentration.

Osmosis can take place in many areas including the cells of our body. The transfer of molecules take place until concentrations at both places become equal. There are many types of osmosis and osmosis solutions, we will discuss about those types in the next section.

Image credits: OpenStax, 0307 Osmosis, CC BY 4.0

Types of osmosis solutions

Osmosis solutions are of three types. They are given in the list below-

1. Isotonic solution- Isotonic solution is that solution in which the concentration of solutes is same both outside and inside the cell.
2. Hypertonic solution– A hypertonic solution is that solution in which the solute concentration is higher outside than inside.
3. Hypotonic solution – A hypotonic solution has higher concentration of solute on the inside than outside.

Types of Osmosis

Osmosis is divided into two types. The two types are discussed In the section below-

1. Endosmosis– When we place a substance in hypotonic solution, the molecules of solvent will move inside the cell making the cell turgid. We can say that it undergoes deplasmolysis. This type of molecule transfer is called as endosmosis.
2. Exosmosis– When a substance is placed in hypertonic solution, the molecules of solvent will move outside the cell making it flaccid and inflexible. We can say that it undergoes plasmolysis. This type of molecule transfer is called as exosmosis.

What is osmotic pressure?

The molecule transfer through the membrane is spontaneous. That is the molecules will transfer on their own by the virtue of concentration difference between the two areas.

To stop this molecule transfer, a certain of pressure is needed. This pressure is called as osmotic pressure. The osmotic pressure can be determined by concentration of solute. The only way to stop diffusion other than applying osmotic pressure is by making the concentrations at both places equal.

Osmotic pressure formula

In above section, we discussed that to find osmotic pressure, we use the value of solute concentration. The formula to calculate osmotic pressure is given below-

Where,

Pi is the osmotic pressure,

M is the molar concentration of solute

R is the gas constant

T is the temperature at which the molecule transfer is taking place

Osmotic pressure examples

The examples of osmotic pressure are given in the list below-

Transport of nutrients in trees

The transport of nutrients from roots to other branches of tree takes place through osmosis. The concentration of nutrients or water is higher at the bottom or roots. The water is transported to other branches where the concentration is lower.

Perspiration

Perspiration in human beings takes place to keep the body cool when it is exercising or getting exposed to heat. The salty water comes out from the body through tiny pores present in our skin.

Absorption of nutrients from soil

The nutrients are absorbed by the roots through osmosis. The concentration of nutrients is high in the soil. This is why it is recommended to add fertilizers to soil so that the soil remains nutrients rich which will eventually promote growth of plant.

Absorption of water in resin

When we dip resins in water, the resin swells up after a certain period of time. This happens due to the fact that higher amount of sugar is present inside resins. So the water rushes inside the resin.

Oxygen transfer to blood

Oxygen transfer to blood is done by the process of diffusion or osmosis. The cells have a semi permeable membrane through which the transfer of oxygen takes place.

Potato in sugar solution

When we put potato in sugar solution, the size of potato reduces because the concentration of water in potato is higher than in the sugar solution. So the water rushes out of potato making it smaller in size.

Fish absorb water through skin and gills

Fishes absorb water or oxygen from water through their skin and gills. They are semi permeable membranes through which the transfer of water molecules take place.

Red blood cells placed in freshwater

The red blood cells have a semi permeable membrane through which molecule transfer can take place. Red blood cells are rich ions and when places in water these cells get swollen due to the fact that water molecules start entering the red blood cells.

Sugar on strawberries

When we sprinkle sugar on strawberries, the outer membrane of strawberry will act as a semi permeable membrane so the water moves to the outer surface of the strawberry. This happens because of the fact that interior has natural sugar and water in it.

Food preservation

Food preservation is direct application of osmosis. The food becomes rich in sugar, vinegar, preservative oils when the food (for example pickle) is placed inside a jar containing these preservatives.

Absorption of digestive food in large and small intestines

The food when reaches to intestines, it is turned into a thick semi fluid called as chyme. When this thick semi fluid or chyme moves in to small intestine, osmosis takes place.

Contact lens-induced dry eye

When we keep lenses in water they are soft and have moisture in it and when we put it on our eye, it absorbs moisture from the eye via osmosis.

Water purification

The water purifiers use the process of reverse osmosis to filter the water from impurities and unwanted minerals. In the process of reverse osmosis, a pressure greater than the osmotic pressure is applied because of which the separation of solute on one side and solvent on the other side takes place. Here the impurities are the solute and solvent is the water.

Also Read:

• Pressure in dynamic equilibrium
• Partial pressure example 2
• Negative pressure example
• Dew point and pressure
• Ocean pressure example
• Vapor pressure example
• Absolute pressure example
• Relative pressure example
• Freezing point and vapour pressure
• Melting point and pressure

Ocean pressure is defined as “pressure in the ocean, which is a result of the weight of the water column pressing down on an object due to gravity”.

In general, the ocean pressure can also be stated as “the weight of the water above pushes on any object below it”.

Detailed explanation of ocean pressure example

In this section, you will learn detailed explanation of above mentioned ocean pressure examples

• Ocean pressure in ocean circulation
• Ocean pressure in human body
• High pressure in depth of ocean
• Pressure of ocean depth in human body
• Pressure at ocean level
• Ocean pressure in living things
• Water pressure in ocean
• Atmospheric pressure in ocean
• Pressure near or above ocean level
• Hydrostatic pressure in ocean
• Measurement of pressure in ocean
• Ocean currents under pressure in ocean
• Ambient pressure in ocean
• Submarine survive water pressure in ocean
• Water pressure at the bottom of Mariana trench in ocean

Ocean pressure in ocean circulation

Ocean circulation is the wide-ranging sheath movement of water in the ocean basins. Ocean circulation is a result of wind pushing which involves pressure on the surface of the water and density difference between the water. Density is a very important property of an ocean because small local changes in density result in local variations in pressure at a given depth, which results in a driving of ocean circulation.

Ocean pressure in Human Body

The human body is one of the most censurable things on the planet. But despite human bodies’ many abilities, human bodies are pretty delicate when we consider the universe around us. For example, we have our pressure in air-filled spaces of our body like our lungs, stomach, and ears our internal pressure is equal to the outside air pressure. But when we jump into the ocean, we feel uncomfortable because our internal pressure is no longer equal to the ambient pressure. This is the reason for our ears hurt when we dive into the ocean.

High pressure in the depth of ocean

Everything in the deep ocean is under a huge estimate of pressure at any depth in the ocean, with all feet an object descends into the ocean more pressure is exerted upon that object hence more water is pushing down and against it. Because of this high pressure in the depth of the ocean scientist and explorers use specially designed equipment like remotely operated vehicles and manned submersibles that can effectuate under extreme pressure.

Pressure of ocean depth in human body

The one reason the human body could not withstand the pressure of the ocean depth without preservation is the variation in volume between pressurized air and pressurized water. When the human body is at a deep enough level, water pressure increases, and the volume of air in the human body decreases because the human body does not have the strength to push back against the water pressure hence the lungs would collapse completely and causes ruptured eardrum and also cause breathing problem and killing instantly.

Pressure at ocean level

The ocean can vary up to 100m from a uniform ellipsoid depending on the density of the earth under it, the continent on which it sits changes the level of the ocean. The gravitational attraction of land pulls more water because of pressure raising the ocean around it.

 Ocean pressure is low near the equator and is called equatorial law if the pressure near the poles is high and is called polar high. The water content at the ocean level is at normal temperature pressure is 1013.25millibars.

Ocean pressure in living things

A band of ocean cade has lung-like swim bladders which help in controlling their buoyancy. The influence of ocean depth is less for organisms without swim bladders which don’t collapse because in the ocean the pressure outside the water is equivalent to the gas inside so they are less affected by pressure than we imagine. Ocean pressure affects the chemical reaction, and organisms adapted to this pressure may experience a metabolic problem. Fish can breathe without using lungs so the pressure difference remains balanced.

Water pressure in ocean

It is the force that pushes water through pipes. The pressure increases by about 1atm for every 10m of water depth. The water pressure in the ocean is 3000 to 9000 pounds per square inch. Water pressure is so high in the ocean because the weight of the water above pushes on any object below it. if the more water is pushing down and against it and more pressure is exerted upon that object.

Atmospheric pressure in ocean

Atmospheric pressure has a direct impact on the ocean level when we wigwag from ocean level to a heave on land, atmospheric pressure drops this is because of less air above we pressing down. For every 10.06m, we go down the pressure increases by 1atm. The force on the surroundings exerted by the high air pressure results in water movement, so in ocean areas high atmospheric pressure low ocean level, and vice-versa.

Pressure near or above ocean level

At ocean level, if the altitude increases the gas molecules decrease leading to a decrease in atmospheric pressure for example when a person or any other marine creature swims, water presses against all sides of them then they feel equal pressure from all directions because of low altitude. The pressure near ocean level is the same as that of when we standing on the land.

Hydrostatic pressure in ocean

When a person dives into the ocean even a few feet, remarkable changes occur you can feel an increase of pressure on your eardrums because of hydrostatic pressure. If the person dives into the ocean the diver reaches 33feet then the pressure is double what it was at the surface. For every 33feet hydrostatic pressure increases by 1atm. Hydrostatic pressure is one of the main reasons why so little of the ocean floor has been explored.

Measurement of pressure in ocean

At the ocean surface we feel 1atm as we descend into the ocean we feel 1atm for every 10m increase in depth. So at 1000m depth the pressure would be 101atm, if we consider the depth of ocean would be 3800m the pressure would be 381times greater than the pressure at the surface.

Ocean currents under pressure in ocean

In a homogeneous ocean having a constant potential density, if the surface of the ocean is tilted then the horizontal pressure differences are possible. In this case, isobaric surfaces are tilted in the deep layers by the same amount as a barotropic field of mass. The unvaried pressure gradient gives current speed uncommitted of depth. The horizontal gradient of pressure is much smaller than the vertical changes in pressure given ocean currents.

Ambient pressure in ocean

Ambient pressure is a junction of the hydrostatic pressure and the atmospheric pressure on the free surface. This increases approximately linear depth, and much greater changes in ambient pressure can be experienced underwater. At ocean level, ambient pressure is about 14.7 pounds per square inch.

Submarine survive water pressure in ocean

Submarines have two hulls, one inside the other, to help them survive, outer hull is waterproof and the inner one is called a pressure hull which is stronger and preventive against immense water pressure. A submarine can control its buoyancy in the ocean. Depending on the depth of the submarine, when the submarine is in dived condition facing external seawater pressure. A submarine can dive is about 2,000feet.

Water pressure at the bottom of Mariana trench in ocean

The deepest know point in an ocean is called as Mariana trench. The water pressure at the bottom of the trench is crushing eight tons per square inch. Piccard’s fish was a sea cucumber it is thought that pressure is so great that calcium cannot exist except in solution. So living near the Mariana trench is impossible for life because of extreme water pressure.

Also, please click to know about 17+ Negative Pressure Example.

Also Read:

• Boiling point and pressure 2
• Negative pressure example
• Pressure in dynamic equilibrium
• Dynamic pressure example
• Gauge pressure example
• Absolute pressure example
• Hydrostatic pressure example
• Dew point and pressure
• Melting point and pressure
• Freezing point and vapour pressure

Negative pressure is defined as “Generated pressure, where the pressure is smaller in one place relative to another place”, that is the pressure below the atmospheric pressure.

In general, the negative pressure can also be stated as ”When the enclosed area has the lower pressure than the area around it, that is when the force will be applied on you by the body.”

This post gives you a detailed explanation of such negative pressure examples

1. Stretching of certain solids
2. Cavitation of liquid
3. Pull of Suction cups
4. Negative pressure during respiration
5. Negative pressure in medium
6. Intrapleural pressure
7. Negative pressure during Gas released into an empty volume
8. Negative pressure in syringes
9. Negative pressure in Dark energy
10. Plants transport water under negative pressure
11. Negative air pressure in pharma industries
12. Shrinkage of solid sphere
13. Negative pressure under isolation
14. Negative pressure in deep well jet pumps
15. Negative pressure in Sucking on a straw
16. Negative pressure in fluid mechanics
17. Trees make negative pressure on water
18. Negative pressure wound treatment

Detailed explanation of Negative pressure examples

In this section, you will learn a detailed explanation of the above-mentioned negative pressure examples.

Stretching of certain solids

We can see negative pressure in solids, we call it negative pressure tension, it happens When we stretch the solid, solids can militate or resist the forces due to the internal attractive force between its molecules

Cavitation of Liquid

When a negative pressure is applied to the liquid, the static pressure of the liquid reseats to down the liquid-vapor pressure leading to the layout of small vapor-filled cavities in the liquid. That is when the negative pressure reaches nearly 9MPa, cavitation occurs.

Pull of suction cups

Suction cups are made up of PVC plastic when a suction cup is sealed inversely on a surface and air is kneaded out of the cup, a negative pressure region is formed inside the suction area, and this negative pressure presses down inside the cup, that creates the suction.

Negative pressure during Respiration

We can see negative pressure in respiration, if we increase the extension of a space the pressure drops, breathing in with the infringement of the chest wall and abdominal wall increases the capacity, pressure drops and the outside air rushes in. in other words we can say that when we inhale, the diaphragm and muscles between our ribs contract, creating a negative pressure inside your chest cavity. The negative pressure draws the air that we can breathe into our lungs.

Negative pressure in medium

When we applied negative pressure to the medium, the expansion of the medium requires work, when a medium is allowed to contract, energy is released that can be used to do useful work.

Intrapleural pressure

The space between the lung and pleura is intrapleural pressure which is a negative pressure because the movement of the lungs Rely upon the pressure inclination among the lungs and pleura. The pressure inside the pleural cavity is generally smaller than the atmospheric pressure, hence, in turn, to operate the air inside the lung, the intrapulmonary pressure and the intrapleural pressure should be negative.

Negative pressure during gas released into an empty volume

Negative pressure was possible when gas was released into an empty volume after some high duration of more or less constant expansion as if owt were absorbing it even order.

Negative pressure in syringes

When we fill a container or bowl with a liquid-like syringe, if the dilute gas is not there in the liquid, the size of the container increases slowly, then there is a possibility of obtaining the negative pressure.

Negative pressure in dark energy

Dark energy is a form of energy postulated to act in opposition to gravity and to occupy the entire universe to accelerate, the gravitational effect of dark energy is repulsive because the dark energy has strong negative pressure, this negative pressure causes a gravitational repulsion, hence the dark energy helps in the expansion of the universe to accelerate.

Plants transport water under negative pressure

The transport process inside the plants mainly occurs in the xylem tissue, xylem sap is transported under negative pressure which means that tension is applied to xylem sap, which can sustain the forces because of hydrogen bonds between water molecules, in plants negative pressure is a result of transpiration, when the sap is under negative pressure the gas bubbles are formed such that the liquid is under tension and is thermodynamically metastable concerning vapor phase.  Negative pressure makes it easier to control and maintain or keep temperature, humidity, carbon dioxide levels, and other contaminants.

Negative air pressure in pharma industries

In pharma industries, negative air pressure maintains the rooms to be clean and is essential to preventing cross-contamination this kind of negative air pressure room are suitable for steroid and chemotherapy.

Shrinkage of solid sphere

When you extract all gas from the sphere up to zero atmospheric pressure and something more. Then solid sphere will try to shrink then we can say that it will be negative pressure.

Negative pressure under isolation

Negative room pressure is an isolation technique used in hospitals to prevent cross-contamination from room to room, it includes ventilation that generates negative pressure to allow air to flow into the isolation room but not escape from the room. Negative pressure rooms in hospitals keep patients with infectious illnesses away from other patients.

Negative pressure in deep well jet pumps

The pumping effect is achieved by using a motive medium such as a gas flow, this produces a dynamic pressure drop in a motive nozzle resulting in negative pressure which accelerates the suction medium by impulse transmission in the mixing nozzle tow throughout. Negative pressure at the deep jet well pumps is when the hydraulic grades at the pump are below their elevation, which occurs generally on the suction side of the pump this suction side is the negative pressure point. The simple technical jet pumps are especially robust and low defensible.

Negative pressure in sucking on a straw

When we suck the liquid on a straw it creates negative air pressure to cause a liquid to flow through a tube against gravity. If the straw has a narrow diameter then we require a greater effort to suck because greater negative pressure is needed to overcome the higher resistance offered by the smaller straws, in another way we can say that, when we drink a juice using a straw the air pressure inside the straw decreases. Due to our sucking the negative pressure is created inside the straw which forces the liquid up along the straw and into our mouth.

Negative pressure in fluid mechanics

Under certain conditions, liquid can stretch, if we pull them they pull back. For example when holding the glass full of water, then the fluid exerted pressure on the glass wall and the glass also exerted equal and opposite pressure on the fluid surface this is because of the stress or tension resulting from the elongation of an elastic body that pressure is negative pressure.

Trees make negative pressure on water

As trees perspire, they lose molecules hence in the stomata of the tree molecular density decreases this lowers the pressure even more negatively. Negative pressure happens when trees undergo transpiration then the water diffuses out the tree leaves at the top and most of the water that scatters the top of the tree.

Negative pressure wound treatment

Negative pressure wound treatment is an advanced technique that will be helping in the healing of the wound in a better and faster way. Negative pressure wound treatment includes the packing of the wound in a sterile or infertile way and a vacuum pump is connected to the dressing so the extra secretions which are being formed inside the wound will be withdrawn with the help of a vacuum, once the machine is on the wound is slowly being pulled together in second.

Also Read:

• Pressure in dynamic equilibrium
• Freezing point and vapour pressure
• Hydrostatic pressure example
• Ocean pressure example
• Partial pressure example 2
• Melting point and pressure
• Gauge pressure example
• Relative pressure example
• Vapor pressure example
• Boiling point and pressure 2

The molecules of the liquid have stored gravitational potential energy at an equilibrium state.

Hydrostatic pressure is due to the liquid at an equilibrium state and this pressure increases as the depth of the liquid increases. Here is a list of hydrostatic pressure examples that we are going to discuss following:-

Dam

The dams are used to store the water to avoid floods and disasters caused due to them. As the height of the water stored in the dam increases, the gravitational potential energy of the water increases simultaneously. When the dam water is released, this stored energy is converted into the kinetic energy of the water.

The hydrostatic pressure due to the molecules of water on each other increases with the depth as the mass overlaying increases with the depth and therefore the pressure exerting on the unit volume of the water also increases.

Pipe

The flow of the water through pipes is because of the pressure difference between the two ends of the pipe that makes it possible for the flow of water. The pressure inside the pipe is increased as the diameter of the pipe is less and the volume of water is more.

Container Filling with Tap Water

As the container kept under tap gets filled with water, the hydrostatic pressure exerted on each other by the molecules of water and on the surface of the container increases with every rise in the volume of the water in the container.

The hydrostatic pressure depends upon the height of the layer of the water in the container. Even if the shape and size of the container and the volume of the water stored in the container differ, the hydrostatic pressure will be equal if the level of the water lies at the same height in all the containers.

Sugar Mixed in Water

If you add sugar cubes to the glass of water, the hydrostatic pressure will be exerted on every cube of water from all sides. That will take time for the sugar to mix well in the water.

Erosion

You must have noticed that collapsing of the surrounding mass of land near the water bodies into the water.

The hydrostatic pressure exerting on the surrounding area in close vicinity of the volume of water which has great storage of potential energy with it, the soil particle is not able to withstand with the hydrostatic pressure for longer once the landmass becomes saturated with the water molecules on absorption.

Deposition

Depending upon the density of the particles and objects dropped in the sea or river water, the objects settle on the seafloor or on the abyssal plain. These objects undergo hydrostatic pressure. This hydrostatic pressure varies depending upon at what depth of the sea the object is present. The lighter objects are carried further in the abyssal plain.

Buoy

It is used to detect the route through the river or is attached to the fishnet to identify and keep the net held at the surface of the water.

This is possible because of the hydrostatic pressure exerted on the buoy by the water molecules present on the surface of the water and also because of the buoyant force exerting on the buoy.

Divers Underwater

Divers underneath the water at depths experiences pressure thrice the atmospheric pressure. This is because the seawater is full of salts and mineral and in addition the hydrostatic pressure due to different molecules is exerted from all the sides of the body of the diver.

This hydrostatic pressure increases as the diver dive deeper and deeper into the sea. The penetration of light also decreases as the hydrostatic pressure increases at every level of water.

Hydraulic Separation Method

It is a method used to separate the minerals and elements from the ore. The ore is mixed with the water, the denser particles settle down while the gangues remain suspended above the surface of the water. These gangue particles are excreted out from the ore.

Rivers and Oceans

Rivers and oceans are storehouses of gravitational potential energy, as the height of the water level increases, we can say that the gravitational potential energy also increases. The hydrostatic pressure increases with the depths. The turbidity of the water is due to the tidal force exerted due to the gravitational pull of the moon.

Precipitation

The precipitation occurs when the two substances get mixed well and settle down to form a hard substance. If the compound is mixed in the water, the particles of the matter will remain suspended in the water due to the hydrostatic pressure exerted on the particles.

The denser matter first settles down and subsequently forms the layers of the matter depending upon the size of the grain of matter and the density.

Osmosis

Osmosis occurs when the water molecules penetrate through the semi-permeable membrane from high concentration to the low concentrated solution.

The hydrostatic pressure is more in a solution that is highly concentrated and thus travels in a low concentrated solution following the law of equilibrium of state.

Water Tankers

The tankers are used to store the water. The water is in a static state. The hydrostatic pressure of the water inside a taken depends upon the height of the volume of water in a tank.

The hydrostatic pressure decreases as the volume of the water in a tank reduces.

Boat and Cruises

The buoyant force is very important to keep the object floating over water which results due to the difference in the pressure on the body of the object. The hydrostatic pressure is exerted on the surface of the boat or cruises floating on the water. If the boat is not kept tightly attached near the shore side then it will sway away with the hydrostatic pressure exerting on it.

Watering Cans

The hydrostatic pressure of the water in a can present at a certain height doesn’t depend upon the height at which the watering can is kept. The hydrostatic pressure inside a can for a particular level of water in a can will be the same even if you kept it on the table or on the ground, perhaps the level of the water does not change.

Frequently Asked Questions

How does the hydrostatic pressure measure?

It is measured using the formula. P=pgh

The hydrostatic pressure increases as the height of the volume of the water level increases, and also depends upon the density of the water and gravitational potential energy.

What is the hydrostatic pressure of the water kept in a tanker of a height of 1.5 meters and is completely full?

Given: h=1.5m

ρ =1000kg/m³

g=9.8ms²

We have,

P=pgh

=1000*9.8*1.5

=14700Pa

Hence, the hydrostatic pressure of the water in a tanker is 14,700 Pa.

What is the hydrostatic pressure in the seawater kept in a glass at a level of 10cm at a temperature of 5⁰C?

Given: h= 10cm= 0.1m

The density of seawater at 5⁰C is p=1028kg/m³

We have,

P=pgh

=1028*9.8*.1

=1007.4 Pa

Hence, the hydrostatic pressure on the seawater inside the glass is 1007.4 Pa.

Also Read:

• Vapor pressure example
• Ocean pressure example
• Does viscosity change with pressure
• Absolute pressure example
• Freezing point and vapour pressure
• Pressure in dynamic equilibrium
• Vapor pressure vs boiling point
• Partial pressure example 2
• Melting point and pressure
• Dynamic pressure example

The pressure measured in terms of the atmospheric pressure by taking it as absolute zero is called a gauge pressure and hence it is a difference between actual pressure and atmospheric pressure.

The gauge pressure is positive if the pressure measured is above the atmospheric pressure and is negative if it is below the atmospheric pressure. Here is a list of gauge pressure example that we are going to discuss in this topic:-

Manometer

The manometer is used to measure the pressure in different systems. It is also used to measure the blood pressure of the patients. It is filled with liquid with one or two ends open. The pressure felt at one end of the tube will push the liquid such that it will raise the height of the liquid on the other hand while decreasing the height on the nearest end where pressure is exerted on the liquid.

At atmospheric pressure, the pressure inside the tube is read as null and the liquid does not move, the gauge pressure is positive when the pressure is experienced on the liquid otherwise it is at the absolute zero point.

Pipeline

Inside a pipe, there is pressure due to the flow of water or any liquid carried through the pipeline otherwise it’s a vacuum. The absolute pressure inside a pipe is the sum of the atmospheric pressure and the pressure of a flow. The gauge attached to measure the pressure inside a pipe will read the atmospheric pressure as zero and will measure the pressure of a flow in a pipe which is gauge pressure.

Pressure Cookers

The pressure inside the cooker is generated due to the accumulation of the vapor upon supplying heat energy to the cooker.

The boiling temperature of the liquid increases as the pressure inside a cooker is higher than the normal atmospheric pressure. The gauge pressure is the vapor pressure inside the cooker and the atmospheric pressure is nullified.

Tap

Tap has a meter to read the volume of water utilized by the users to ease the water bill payments. The gauge meter attached to the pipe is used to measure the flow of volume of water through a pipe. It actually works on the pressure exerted on the gauge due to the flowing water.

Gas Cylinders

The cylinders are filled with liquid petroleum gas and maintained under a pressure greater than atmospheric pressure.

When the knob is opened, the liquid phase is converted into the gaseous state on overcoming the high-pressure conditions and this gas runs through a pipe to the burner. The gauge pressure in this case is independent of the atmospheric pressure inside a cylinder.

Compressors

The compression is caused when the equal and opposite forces are exerted on the body from at least two directions. It results in the reduction of the molecular spaces within the object. The gauge pressure is the force exerted on the unit area of the object and is obviously positive as the pressure impose is greater than the atmospheric pressure.

Cartesian Diver

It is a small toy where a toy diver is inserted into a bottle of water and it remains floating on the top layer of water with half dip inside until the force is imposed on the surface of the bottle then it dips and reaches the bottom surface of the bottle.

This happens because the molecular force exerting on the surface of the bottle from both sides is canceled out upon putting the pressure on the bottle and the only force that comes into action is the force from the knob of the bottle above.

Water Pumps

The water through a pipe runs because of the pressure difference. The water moves from the high-pressure area to the low-pressure region.

The pump is used to apply the pressure greater enough than the pressure of the water flow to push or pull the flow of water through a pipe. The gauge pressure is more than the atmospheric pressure and hence is positive.

Deep-Sea

The seawater is a mixture of different salts and minerals and the pressure is almost thrice that of the atmospheric pressure. The gauge pressure is positive beneath the surface of the seawater. Under this pressure, it becomes difficult for sea divers to breathe in and hence carries oxygen cylinder while diving.

Bicycle Pump

It is used to fill the air in the tires of the bicycle. The pressure gauge attached to the pump will read the pressure inside the tire on connecting to the tire to pump the air. The pressure of the gas inside the tire will keep on increasing as the molecular pressure rises with an increasing volume of the gas inside the tube.

After filling the air in a tire and as you separate the pump from the bicycle tire, the pressure gauge should read the atmospheric pressure but it pressure gauge read zero pressure point after disconnecting. The atmospheric pressure is taken as the absolute null point of the pressure gauge and hence it read the atmospheric pressure as zero.

Wind Pressure

The gauge can be used to measure the wind speed by calculating the pressure exerted on the object. The gauge will calculate the pressure due to the wind force exerted on the unit surface area of the object relative to the atmospheric pressure. The gauge will read atmospheric pressure as a null pressure and hence we can estimate the wind pressure.

Oxygen Cylinder

The oxygen is stored in the cylindrical container in the form of a liquid state maintained at high pressure. To measure the pressure inside this cylinder, the cylinders are attached to the pressure gauge.

By opening the knob of the cylinder, the oxygen is converted into the gaseous form due to pressure difference and flows through the pipe to the oxygen mask attached to the pipe.

Soft Drink Bottles

The soft drinks are preserved by packing the bottles and inserting the carbon dioxide gas. You must have observed the effervescence in the soft drinks immediately after opening the bottle of soft drinks or soda bottles; this is because the pressure created in the bottle due to these gas molecules is released on removing the cap over the bottle.

Boilers

The pressure gauge is used to measure the pressure due to the boiler that is used in many industries. The pressure is generally created because of the evaporated steam due to the boilers as the immense heat is utilized to break the bonds between the molecules and convert the liquid phase into the gaseous phase.

Fire Extinguisher

The pressure inside the cylinder is due to the carbon dioxide gas stored in it that is released during emergencies to extinguish the fire. The pressure inside the cylinder is around 185-195 psi and is gauge pressure excluding the atmospheric pressure in which the cylinder is present.

Frequently Asked Questions

How to measure the gauge pressure from the absolute pressure?

We can measure the gauge pressure using the formula

P_gauge=P_abs-P_atm

The absolute pressure is the sum of the atmospheric pressure and the gauge pressure exerted on the system at constant atmospheric pressure, hence we can calculate the gauge pressure using the formula given above.

What is relative pressure?

It is the pressure relative to the atmospheric pressure.

The relative pressure is the pressure higher or below the atmospheric pressure with respect to the atmospheric pressure condition taking it as a null pressure point same as the gauge pressure.

Also Read:

• Negative pressure example
• Absolute pressure example
• Dynamic pressure example
• Relative pressure example
• Hydrostatic pressure example
• Pressure in dynamic equilibrium
• Osmotic pressure example
• Freezing point and vapour pressure
• Does viscosity change with pressure
• Ocean pressure example

Freezing point depression and vapor pressure lowering are two crucial colligative properties of solutions, which are directly proportional to the concentration of the solute present in the solution. These properties play a vital role in understanding the behavior of solutions and have numerous applications in various fields of science and engineering.

Understanding Freezing Point Depression

The freezing point depression is the decrease in the freezing point of a solution compared to that of the pure solvent. This phenomenon is described by the following equation:

ΔTf = m × Kf

Where:
– ΔTf is the change in freezing point (°C)
– m is the molal concentration of the solute (mol/kg)
– Kf is the freezing point depression constant or cryoscopic constant (°C·kg/mol)

The values of Kf for various solvents are listed in the table below:

Solvent	Kf (°C·kg/mol)
Water	1.86
Benzene	5.12
Ethanol	1.99
Acetic Acid	3.90

To calculate the freezing point of a solution, you can follow these steps:

1. Determine the molal concentration of the solute (m).
2. Multiply the molal concentration by the freezing point depression constant (Kf) to find the change in freezing point (ΔTf).
3. Subtract the change in freezing point (ΔTf) from the freezing point of the pure solvent to find the freezing point of the solution.

For example, let’s consider a 0.33 m solution of a nonvolatile, nonelectrolyte solute in benzene:

1. The molal concentration (m) is 0.33 mol/kg.
2. The freezing point depression constant (Kf) for benzene is 5.12 °C·kg/mol.
3. The change in freezing point (ΔTf) is calculated as: ΔTf = m × Kf = 0.33 mol/kg × 5.12 °C·kg/mol = 1.69 °C.
4. The freezing point of the pure benzene is 5.5 °C.
5. The freezing point of the solution is 5.5 °C – 1.69 °C = 3.81 °C.

Understanding Vapor Pressure Lowering

The vapor pressure of a solution is lower than that of the pure solvent, and the decrease in vapor pressure is directly proportional to the concentration of the nonvolatile solute present in the solution. This relationship is described by the following equation:

ΔP = P0 – P = -x × K

Where:
– ΔP is the change in vapor pressure (torr)
– P0 is the vapor pressure of the pure solvent (torr)
– P is the vapor pressure of the solution (torr)
– x is the mole fraction of the solvent
– K is the vapor pressure lowering constant (torr)

To calculate the vapor pressure of a solution, you can follow these steps:

1. Determine the mole fraction of the solvent (x).
2. Multiply the mole fraction of the solvent by the vapor pressure lowering constant (K) to find the change in vapor pressure (ΔP).
3. Subtract the change in vapor pressure (ΔP) from the vapor pressure of the pure solvent (P0) to find the vapor pressure of the solution (P).

For example, let’s consider a 0.1 m aqueous solution of glucose at 25 °C:

1. The mole fraction of the solvent (water) is calculated as:
   x = nH2O / (nH2O + nglucose) = 55.56 mol / (55.56 mol + 0.1 mol) = 0.998
2. The vapor pressure lowering constant (K) for water at 25 °C is 1.052 × 10^3 torr·kg/mol.
3. The change in vapor pressure (ΔP) is calculated as:
   ΔP = -x × K = -0.998 × 1.052 × 10^3 torr·kg/mol = -1.05 torr
4. The vapor pressure of pure water at 25 °C is 23.75 torr.
5. The vapor pressure of the solution is 23.75 torr – 1.05 torr = 22.70 torr.

Determining Molar Mass Using Freezing Point and Vapor Pressure

The freezing point and vapor pressure of a solution can also be used to determine the molar mass of an unknown solute. Let’s consider an example:

A solution of 4.00 g of a nonelectrolyte dissolved in 55.0 g of benzene is found to freeze at 2.32 °C. Determine the molar mass of the solute.

1. Determine the change in freezing point:
   ΔTf = 5.5 °C – 2.32 °C = 3.18 °C
2. Determine the molal concentration from Kf, ΔTf, and the mass of solvent:
   m = ΔTf / Kf = 3.18 °C / 5.12 °C·kg/mol = 0.62 mol/kg
3. Determine the number of moles of solute in the solution:
   n = m × mass of solvent = 0.62 mol/kg × 0.055 kg = 0.034 mol
4. Determine the molar mass of the solute:
   M = mass of solute / number of moles = 4.00 g / 0.034 mol = 117.6 g/mol

In summary, freezing point depression and vapor pressure lowering are important colligative properties of solutions that can be used to determine the molar mass of an unknown solute. The values of Kf for various solvents are crucial in these calculations.

Additional Resources

For further information and examples on freezing point depression and vapor pressure lowering, you can refer to the following resources:

Reference:
– Freezing-Point Depression and Boiling-Point Elevation of Solutions
– Colligative Properties
– Colligative Properties- Freezing Point Depression, Boiling Point Elevation, and Osmosis
– Colligative Properties: Freezing-Point Depression and Molar Mass

Dew point and pressure are critical variables in understanding the behavior of gases and liquids in various industrial processes and meteorological applications. Dew point is the temperature at which a given volume of air at a certain atmospheric pressure becomes saturated with water vapor, leading to condensation and the formation of dew. The relationship between dew point and pressure is complex, as changes in pressure can significantly affect the dew-point temperature.

Understanding Dew Point

Dew point is a measure of the absolute moisture content in the air, and it is expressed in degrees Celsius (°C) or degrees Fahrenheit (°F). The dew point is the temperature at which the air becomes saturated with water vapor, and any further cooling will result in the formation of dew or frost.

The dew point is dependent on the pressure of the gas being measured, and it can be stated in different ways:

1. °C dew point: The temperature at which water vapor in the air condenses into liquid water.
2. °C frost point: The temperature at which water vapor in the air condenses into solid ice (frost).
3. °C td: The temperature at which the air becomes saturated with water vapor.

Each of these parameters provides operators with slightly different information, which can be useful in various applications. For example, in applications where operators need to avoid moisture condensing, ensuring the dew point temperature of the gas is below the lowest possible ambient temperature means no liquid moisture will condense and there will be no risk of blockages due to ice.

The Relationship between Dew Point and Pressure

The relationship between dew point and pressure is complex, as increasing pressure affects the dew-point temperature. This is because the temperature at which the water vapor in gas then condenses is dependent on the absolute moisture content and pressure of the gas.

The formula for calculating the dew point temperature (Td) is:

Td = (b * y / (a - y)) + c

Where:
– a, b, and c are constants that depend on the type of gas and the pressure range.
– y is the mole fraction of water vapor in the gas.

As the pressure of the gas increases, the dew point temperature also increases. This is because the higher pressure causes the water vapor to condense at a higher temperature.

In applications where water dew points are measured in order to avoid condensation, such as natural gas pipelines and compressed air systems, changes in pressure can influence the dew point calculation of such systems. Therefore, it is essential to know the pressure at the sampling point where the dew-point is measured.

Pressure Dew Point (PDP)

Pressure dew point (PDP) is the temperature at which water condenses in a pressurized gas, and it is essential when working with compressed air. The PDP is the temperature at which the water vapor in the gas condenses, and it is dependent on the absolute moisture content and pressure of the gas.

The formula for calculating the pressure dew point (PDP) is:

PDP = (b * y / (a - y)) + c

Where:
– a, b, and c are constants that depend on the type of gas and the pressure range.
– y is the mole fraction of water vapor in the gas.

It is important to note that the PDP is different from the atmospheric dew point, as the PDP is influenced by the pressure of the gas.

Measuring Dew Point and Pressure

Instruments used to measure dew point and moisture contents are different in several applications, and Process Sensing Technologies (PST) offers a range of solutions, including:

1. Portable Dew Point Meters: These handheld devices are used to measure the dew point of gases in various industrial applications, such as compressed air systems, natural gas pipelines, and refrigeration systems.
2. Dew-Point Transmitters: These devices are used to continuously monitor the dew point of gases in industrial processes, providing real-time data for process control and optimization.
3. Hygrometers: These instruments measure the relative humidity and temperature of the air, which can be used to calculate the dew point.
4. Humidity and Temperature Calibration Systems: These systems are used to calibrate and verify the accuracy of humidity and temperature sensors, ensuring reliable dew point measurements.
5. Process Moisture Analyzers: These specialized instruments are used to measure the moisture content in various industrial processes, such as natural gas processing, petrochemical production, and power generation.
6. Hydrocarbon Dew Point Analyzers: These analyzers are used to measure the dew point of hydrocarbon gases, which is essential for the safe and efficient operation of natural gas pipelines and processing facilities.

Practical Applications and Examples

Dew point and pressure are critical variables in a wide range of industrial and meteorological applications, including:

1. Compressed Air Systems: Monitoring the dew point of compressed air is essential to prevent moisture condensation, which can lead to equipment damage and process disruptions.
2. Natural Gas Pipelines: Measuring the dew point of natural gas is crucial to ensure that the gas meets quality specifications and to prevent the formation of hydrates, which can cause blockages in the pipeline.
3. Refrigeration Systems: Dew point monitoring is important in refrigeration systems to prevent the formation of ice, which can reduce the efficiency of the system and cause equipment failure.
4. Meteorology: Dew point is a key parameter in weather forecasting, as it is used to determine the likelihood of precipitation and the formation of fog or dew.
5. Pharmaceutical and Food Processing: Dew point monitoring is essential in these industries to ensure product quality and prevent microbial growth.

Here are some numerical examples to illustrate the relationship between dew point and pressure:

Example 1:
– Pressure: 1 atm (101.325 kPa)
– Absolute humidity: 0.01 kg/m³
– Dew point temperature: 10°C

Example 2:
– Pressure: 10 atm (1013.25 kPa)
– Absolute humidity: 0.01 kg/m³
– Dew point temperature: 30°C

As you can see, the dew point temperature increases as the pressure increases, even though the absolute humidity remains the same.

Conclusion

Dew point and pressure are critical variables in understanding the behavior of gases and liquids in various industrial processes and meteorological applications. The relationship between dew point and pressure is complex, and it is essential to know the pressure at the sampling point where the dew-point is measured. Pressure dew point (PDP) is the temperature at which water condenses in a pressurized gas and is crucial when working with compressed air. By understanding the principles and practical applications of dew point and pressure, professionals in various industries can optimize their processes, ensure product quality, and prevent equipment failures.

References

1. Vaisala. (2019, September). What is Dew Point and How to Measure It? [Blog post]. https://www.vaisala.com/en/blog/2019-09/what-dew-point-and-how-measure-it
2. Process Sensing Technologies. (n.d.). Dew Point Definition and How to Measure It for Industries. [Blog post]. https://www.processsensing.com/en-us/blog/dew-point-definition-and-how-to-measure-it-for-industries.htm
3. Calculator.net. (n.d.). Dew Point Calculator. https://www.calculator.net/dew-point-calculator.html
4. Process Sensing Technologies. (n.d.). Pressure Dew Point Conversion Tables. [Blog post]. https://www.processsensing.com/en-us/blog/pressure-dew-point-conversion-tables.htm

In this article I’m going to explain what dynamic pressure is with 12+ dynamic pressure example.

Dynamic pressure can be defined as the change in kinetic energy per unit mass of an incompressible fluid. The mathematical formula of Dynamic pressure is- Pd=1/2ᑭv^2 where ᑭ is the mass per unit volume and v is the velocity of the fluid.

12+ dynamic pressure example are written below:

1. Combustion Engine of a car
2. Turbomachines
3. Spacecrafts and Aircrafts
4. Oscillations
5. Processes related to Production 
6. Robotics 
7. Fluid Control processes
8. Pharmaceutical needs
9. Blast Waves 
10. Ballistics 
11. Automotive Industry
12. Frequency and Amplitude measurement

From Bernoulli’s theorem we can say that for an incompressible fluid the sum of change in pressure energy (p/ᑭ),kinetic energy(1/2v^2) and potential energy per unit mass(gh) is always constant. So the mathematical form of Bernoulli’s theorem is-

p/ᑭ+1/2v^2+gh=constant,where g is the gravitational acceleration. So here the second term of Bernoulli’s equation refers to the Dynamic Pressure(Pd) of a fluid. Normally mathematical expression of kinetic energy is 1/2.m.v^2. But here we have taken kinetic energy per unit mass that is why the expression has become 1/2v^2.

                                Mass(m)= volume(V) * density(ᑭ)

                                            here,V=1 unit,

                                   So, m=ᑭ and  1/2mv²= 1/2ᑭv^2=Pd

1.Combustion Engine of a car

Combustion engine of a car is one of the most important dynamic pressure example. Today the whole world is concerned about emissions of poisonous gasses from the combustion chamber of a car. So the measurement of dynamic pressure inside the gas cylinder of a car can make us able to detect whether the level of emission in a car is low or high.

2. Turbomachines

Turbomachines are another important dynamic pressure example. Turbomachines are those machines which use blades to convert wind energy and mechanical energy into electrical or thermal energy. Examples of turbomachines are turbines,ceiling fans,exhaust fans,compressors etc. To measure the efficiencies of the turbomachines and to detect their sources of losses dynamic pressure measurement is necessary. To measure the value of thrust and to identify if the pressure is excess there dynamic pressure is measured in the rocket propulsion system.

3. Spacecrafts and Aircrafts

Construction and designing of spacecrafts and aircrafts need a stable structure to be used to fulfill human necessities. Unstable pressure within the spacecrafts and aircrafts can lead to complete destruction of them which in turn can cause deaths of many people. To avoid this problem dynamic pressure should be calculated accurately.

Sometimes this unstable pressure within the construction of vehicles and bridges can cause them to be damaged.

4. Oscillations

In acoustics mainly the oscillations that are low amplitude in nature measure the acoustic or sound pressure related to atmospheric pressure. This pressure is measured in decibel units. This pressure includes the noises within a house and outside the house,other external noises of vehicles,machinery of industrial areas etc. 

The mathematical expression to calculate this oscillation pressure is

 dB= 20 log(P/P0) where P is the gauge pressure and P0 is the atmospheric pressure here.

 5. Processes related to Production

In the processes of plastic production, expulsion and die casting are done at a very high pressure but at very low frequency. So here in the production industry measurement or calculation of dynamic pressure is a much needed condition to extend the business and to increase both the quality and quantity of materials. It is another important dynamic pressure example to be noted.

6. Robotics

In today’s world robotics is moving at a very  fast  rate which will omit all human labor one day. In the body parts of robots we use pressure sensors to measure dynamic pressure. This in turn makes the robot work perfectly. These sensors usually act at a very low frequency. It is another notable dynamic pressure example.

7. Fluid Control processes

Machines based on hydraulic pressure like valves,pumps,engines,compressors etc help to control the movements of parts of objects. To know if these machines are acting perfectly the dynamic pressure should be calculated at a very high amplitude. Whenever a special activity is to be catched then a very high frequency should be maintained. It is one of the important dynamic pressure example.

Otherwise all operations within these machines require a low range of frequency. But in case of operations of pneumatic machines we require a low range of frequency and a low amplitude.

8. Pharmaceutical needs

In the blood pressure measurement of a patient there are two steady values of systolic and diastolic pressure. So the measurement of dynamic pressure gives us additional information about a patient’s health condition. Other than this orthopaedists use the method of walking of patients to measure their foot pressure which helps them to accurately identify the problem and to treat them properly.  

In case of accidents or any other sudden health problem  dynamic pressure measurement of body parts is also done in order to cure them.

9. Blast Waves 

When an explosive bursts it emits a pulse of pressure which is termed as blast wave. This can be an air blast or an underwater blast wave. Here the dynamic pressure measurement helps in two different ways. One is when the explosives need to test their maximum capability of destruction and the other is when the battalions want to check whether their shelters are able to stand firm against any kind of air blasts or not.

10. Ballistics

In the chamber of ballistic missiles,guns and other weapons,the value of dynamic pressure should be checked in order to resist any kind of explosions or other dangerous effects. This is another remarkable dynamic pressure example.

11. Automotive Industry

Exhaust pressure inside a vehicle is also measured. This is basically a parameter to control emissions from a vehicle. To achieve low emissions of hazardous gasses How much fuel should be injected in a cylinder of a vehicle to achieve low emissions of hazardous gasses is decided by this parameter.

12. Frequency and Amplitude measurement

Frequency and amplitude are heavily affected by the measurement of dynamic pressure in an instrument. Temperature range,fluid medium of which the dynamic pressure is being measured,chemical conditions etc also affect the value of dynamic pressure of a fluid. It is another notable dynamic pressure example.

Also, please click to know about 16+ Relative Pressure Example.

Also Read:

• Freezing point and vapour pressure
• Melting point and pressure
• Does viscosity change with pressure
• Relative pressure example
• Hydrostatic pressure example
• Vapor pressure vs boiling point
• Osmotic pressure example
• Gauge pressure example
• Vapor pressure example
• Negative pressure example