Chemistry Project on Evaporation of Liquid
Chemistry Project on Evaporation of Liquid
Acknowledgement
I would like to show my gratitude to my Chemistry Teachers Ms Seema More without whose support and encouragement this project could never have have taken the present shape . I would also like to thank my lab incharge Mr. Kakde For helping Me out During The Practical Part Of This Project.
Aim
Acknowledgment
I am are greatly thankful for the cooperation and help from the Community Science Center (CSC) authorities and the Chemistry lab staff for the successful completion of this investigatory project in the CSC Chemistry lab. Without their help and proper guidance my project might not have completed.
Index
1. Introduction
2. Theory
3. Objectives of project
4. Experiment No.1
Theory
Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state.
The thermal motion of a molecule must be sufficient to overcome the surface tension of the liquid in order for it to evaporate, that is, its kinetic energy must exceed the work function of cohesion at the surface. Evaporation therefore proceeds more quickly at higher temperature and in liquids with lower surface tension. Since only a small proportion of the molecules are located near the surface and are moving in the proper direction to escape at any given instant, the rate of evaporation is limited. Also, as the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid thus decreases.
If the evaporation takes place in a closed vessel, the escaping molecules accumulate as a vapor above the liquid. Many of the molecules return to the liquid, with returning molecules becoming more frequent as the density and pressure of the vapor increases. When the process of escape and return reaches equilibrium, the vapor is said to be “saturated,” and no further change in either vapor pressure and
Acknowledgement
I would like to show my gratitude to my Chemistry Teachers Ms Seema More without whose support and encouragement this project could never have have taken the present shape . I would also like to thank my lab incharge Mr. Kakde For helping Me out During The Practical Part Of This Project.
Aim
Acknowledgment
I am are greatly thankful for the cooperation and help from the Community Science Center (CSC) authorities and the Chemistry lab staff for the successful completion of this investigatory project in the CSC Chemistry lab. Without their help and proper guidance my project might not have completed.
Index
1. Introduction
2. Theory
3. Objectives of project
4. Experiment No.1
Theory
Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state.
The thermal motion of a molecule must be sufficient to overcome the surface tension of the liquid in order for it to evaporate, that is, its kinetic energy must exceed the work function of cohesion at the surface. Evaporation therefore proceeds more quickly at higher temperature and in liquids with lower surface tension. Since only a small proportion of the molecules are located near the surface and are moving in the proper direction to escape at any given instant, the rate of evaporation is limited. Also, as the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid thus decreases.
If the evaporation takes place in a closed vessel, the escaping molecules accumulate as a vapor above the liquid. Many of the molecules return to the liquid, with returning molecules becoming more frequent as the density and pressure of the vapor increases. When the process of escape and return reaches equilibrium, the vapor is said to be “saturated,” and no further change in either vapor pressure and