Home
Class 11
CHEMISTRY
Why does the boundary between liquid pha...

Why does the boundary between liquid phase and gaseous phase disappear on heating a liquid upto critical temperature in a closed vessel ? In this situation what will be the state of the substance ?

Text Solution

Verified by Experts

when the liquid is heated upto critical temperature. The density of the liquid and gaseous phase of a substance become equal. As a result, the liquid passes into the gaseous state continuously and the boundry of separation dissappears. The substance is said to be in the fluid state which includes both the liquid and gaseous states, For details consult section 5.22.
Promotional Banner

Similar Questions

Explore conceptually related problems

What happens if a liquid is heated to the critical temperature of its vapour?

What is the nature of equilibrium between the liquid surface and its vapours in a closed vessel ?

Each phase of a material can exits only in certain regions of pressure and temperature . P-T phase diagrams, in which pressure is plotted versus temperature, show the regions corresponding to various phases and phase transformations . P-V diagrams, on the other hand , can be used to study pressure volume relationship at a constant temperature. If the liquid and gaseous phases of a pure substances are heated together in a closed container, both the temperature and the vapor pressure will increase until a point is reached at which the two phases can no longer be distinguished from one another. The temperature and pressure at which this occurs are called the critical temperature and pressure. Exceeding either of these parameters, by itself ,will cause the "gas"//"liguid" phase transition to disappear. if the other variable is then changed as well, while the first variable is maintained above its critical point , a gradual transition will occur between the gaseous and liquid phases, with no clear boundary.(The liquid and solid phases, on the other hand , maintain a distinct boundary at all pressure above the triple point). Shown in figure is a combined P-T phase diagram for material A and B . Which is true about the substance in figure?

Each phase of a material can exits only in certain regions of pressure and temperature . P-T phase diagrams, in which pressure is plotted versus temperature, show the regions corresponding to various phases and phase transformations . P-V diagrams, on the other hand , can be used to study pressure volume relationship at a constant temperature. If the liquid and gaseous phases of a pure substances are heated together in a closed container, both the temperature and the vapor pressure will increase until a point is reached at which the two phases can no longer be distinguished from one another. The temperature and pressure at which this occurs are called the critical temperature and pressure. Exceeding either of these parameters, by itself ,will cause the "gas"//"liguid" phase transition to disappear. if the other variable is then changed as well, while the first variable is maintained above its critical point , a gradual transition will occur between the gaseous and liquid phases, with no clear boundary.(The liquid and solid phases, on the other hand , maintain a distinct boundary at all pressure above the triple point). Shown in figure is a combined P-T phase diagram for material A and B . If heat is added to solids A and B , each in a container that is open to the atmosphere :-

The diagram below shows the change of phases of a substance on a temperature vs time graph on heating the substance at a constant rate. What is the boiling and melting point of the substance ?

A thermally insulated vessels contains two liquids with initial temperature T_(1) and T_(2) and specific heats C_(0) and 2C_(0) , separted by a non conducting partition. The partition is removed, and the difference between the initial temperature of one of the liquids and the temperature T established in the vessel turns out to be equal to half the difference between the initial temperatures of the liquids. Determine the ratio of M_(1)//M_(2) of the masses of the liquids.

A substance on heating, undergoes (i) a rise in its temperature, (ii) a change in its phase without change in its temperature. In each case, state the change in energy of molecules of the substance.

Heat supplied to a solid changes it into liquid. What is this change in phase called ?

What is the state of dispersed phase and the dispersion medium (solid, liquid or gas) in smoke, mist, milk and gels?

A "flow calorimeter" is used to measure the specific heat of a liquid. Heat is added at a known rate to a stream of the liquid as it passes through the calorimeter at known rate, then a measurement of the resulting temperature difference between the in flow and the out flow points of the liquid stream enables us to compute the specific heat of the liquid. A liquid of density 0.85 g//cm^(3) flows through a calorimeter at the rate of 8.0 cm^(3)//s . heat is added by means of a 250 watt electric heating coil, and a temperature difference of 15^(@)C is established in steady state conditions between the in flow and out flow points. Q. Specific heat of the liquid is