How does volume affect vapor pressure

If this container's lid was acting like a piston or something and that was what you used to change the volume, naturally the gas molecules would be compressed but they don't want to get compressed - so they escape into the solution - because the interface between the liquid and the gas molecules would compose of strong intermolecular forces to drag those molecules back into the liquid.

Let's get the assumptions clear. Le Chatelier's principle states that a system, when one of it's properties is changed, will act in such a way as to counteract this change. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. Featured on Meta. Now live: A fully responsive profile. Related 3. Hot Network Questions. Vapor pressure is the pressure exerted by a liquid back on the atomosphere. Vapor pressure depends on the nature of the liquid and the temperature.

An example is water's vapor pressure, which happens to be relatively low because of the hydrogen bonding between the water molecules. No matter what volume the water is, the vapor pressure of the water is the same as long as the temperature is not change.

Why is vapor pressure independent of volume? The higher the vapor pressure of a material at a given temperature, the lower the boiling point. Air pressure also affects evaporation. If air pressure is high on the surface of a body of water, then the water will not evaporate easily.

The pressure pushing down on the water makes it difficult for water to escape into the atmosphere as vapor. Temperature, of course, affects how quickly evaporation happens. Vapor pressure increases as liquid temperature increases, so evaporation rate also increases. When vapor pressure reaches atmospheric pressure, boiling occurs. Yes this what the evaporation is, this will occur at any temperature. When vapour pressure becomes equal to atm pressure then boiling starts.

Pressure: when the external pressure is: less than one atmosphere, the boiling point of the liquid is lower than its normal boiling point. Vapor pressure is the pressure caused by the evaporation of liquids.

Three common factors that influence vapor press are surface area, intermolecular forces and temperature. The opposite is also true if one boils water at an altitude lower than sea level.

Vapor pressures are dependent only on temperature and nothing else. The vapor pressure of a liquid does not depend on the amount on the liquid in the container, be it one liter or thirty liters; at the same temperature, both samples will have the same vapor pressure. Vapor pressures have an exponential relationship with temperature and always increase as temperature increases Figure 2: Vapor Pressure Curves.

It is important to note that when a liquid is boiling, its vapor pressure is equal to the external pressure. For example, as water boils at sea level, its vapor pressure is 1 atmosphere because the external pressure is also 1 atmosphere. Generally a substance's vapor pressure increases as temperature increases and decreases as temperature decreases i.

This chart shows that this trend is true for various substances with differing chemical properties. The change in vapor pressure of a pure substance as temperature changes can be described using the equation known as the Clausius-Clapeyron Equation :. If the vapor pressure of water at K is Assume K to be T 1 and We know the enthalpy of vaporization of water is J mol Therefore we plug in everything we are given into the equation.

Step 3: To isolate the variable, we need to get rid of the natural log function on the left side. To do so, we must exponentiate both sides of the equation after calculating the numerical value of the right side of the equation:. The vapor pressure of water at K is At what temperature is the vapor pressure of water mmHg? Step 1: Once again this can be solved using the Clausius-Clapeyron equation. So plug everything we know into the Clausius-Clapeyron Equation and we get:.

Step 2: We can solve the right side of the equation for a numerical answer and we can simplify the right side of the equation to:. Step 4: After subtracting The rounding in this problem will make a relatively large difference in mmHg mmHg.