An experiment on the value of the heat of vaporization of water
The definition of boiling can be explained relative to the vapor pressure of a liquid and the external pressure applied to that liquid. The experiment is useful in enumerating several important basic chemistry concepts.
It is highly recommended that a few boiling stones be placed in the round bottom-boiling flask in order to minimize bumping that occurs even more severely under reduced external pressure.
Under the increased external pressure, boiling will cease immediately.
If instead, according to the integrated form of the Clausius-Clapeyron equation, the logarithm of the vapor pressure is plotted versus the reciprocal of the kelvin temperature, a straight line is obtained.
These concepts include the following: 1.
Heat of vaporization formula
The water flow to the aspirator is set to maximum to provide highest vacuum. Boiling can typically be achieved at temperatures of fifty degrees Celsius or lower, at the lower external pressures. Procedure: It has been found that it is most convenient to start the experiment at the lowest possible pressure. At this point it is necessary to try to obtain a stable temperature and pressure. This condition is accomplished by closing the regulator bleed valve. Measuring Specific Latent Heat of Vaporization of Water Objective To enable the student to measure the specific latent heat of vaporization of water by an electric method Theory The specific latent heat of vaporization is the amount of heat that is needed change 1 Kg of a substance in the liquid state into the gas state at the boiling point. This experiment can be used to help students to develop new techniques in the preparation of graphs. The temperature of the sample in the boiling flask distilled water is increased until boiling commences. It is highly recommended that a few boiling stones be placed in the round bottom-boiling flask in order to minimize bumping that occurs even more severely under reduced external pressure. Also, a pressure-regulating device a needle valve that is part of a Bunsen burner base will work , and a thermometer are necessary. In connection with this, the concept of reading slopes and the meaning of the slope intercept form of an equation for a straight line, should become apparent following successful completion of the experiment.
The water flow to the aspirator is set to maximum to provide highest vacuum. It should be remembered that glass, being a poor conductor of heat, could have a high surface temperature immediately after removing the heat source.
Therefore, everyone obtains the same raw data.
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