Saturated and Unsaturated Vapour Pressure
Saturated and Unsaturated Vapour Pressure
What is a saturated solution?
If in a water sugar solution, the amount of dissolved sugar is equal to the maximum amount that a given amount of water can dissolve at a certain temperature, then that solution is called a saturated solution.
What is an unsaturated solution?
If in a water sugar solution, the amount of dissolved sugar is less than that amount that a given amount of water can dissolve at a certain temperature, then that solution is called a saturated solution.
What is saturated vapour?
At a certain temperature in an enclosed space, if the amount of vapour present is equal to the maximum vapour capacity of that space, then that vapour is called saturated vapour.
What is unsaturated vapour?
At a certain temperature in an enclosed space, if the amount of vapour present is less than the maximum vapour capacity of that space, then that vapour is called unsaturated vapour.
What is vapour pressure?
Vapour enclosed in a container behaves like gas which means vapour molecules move randomly and erratically in different directions and collide with each other and the container wall and as a result, create pressure. This pressure is called vapour pressure.
What is saturated vapour pressure?
The pressure of saturated vapour at a certain temperature is called saturated vapour pressure.
What is unsaturated vapour pressure?
The pressure of unsaturated vapour at a certain temperature is called unsaturated vapour pressure.
What is called Torricelli's vaccum?
When a one-meter-long one-end closed glass tube is filled with pure mercury and is put upside down on a mercury-filled pot, the mercury level inside the glass tube goes down a little and settles down at a certain height and thus a vacuum is created on top of the mercury. This void is called Torricelli's vacuum.
Saturated vapour pressure increases with temperature rise
If the temperature of Torricelli's vacuum is increased when that space is saturated with vapour, it is seen that more water is evaporating and mercury column height is going down. Therefore, it can be realized that saturated vapour pressure increases with temperature rise.
Saturated vapour pressure doesn't depend on vapour volume
Having Torricelli's vacuum saturated with water vapour, if the glass tube is gradually lowered, it is seen that the volume of Torricelli's vacuum is decreasing while mercury column height remains the same even if it remains so until Torricelli's vacuum disappears. It can be postulated from this event that at a fixed temperature, saturated vapour pressure doesn't depend on the volume of vapour.
Saturated vapour pressure depends on the nature of liquid
If any liquid other than water is inserted into Torricelli's vacuum, it is seen that saturated vapour pressure is different from that of water.
