+---------------------+--------------+
| | Degrees |
| | Fahrenheit |
+---------------------+--------------+
| Ammonia | 140 |
| Bromine | 145 |
| Alcohol | 173 |
| Benzine | 212 |
| Water | 212 |
| Average Sea Water | 213.2 |
| Saturated Brine | 226 |
| Mercury | 680 |
+---------------------+--------------+
Total Heat of Evaporation--The quantity of heat required to raise a unit
of any liquid from the freezing point to any given temperature, and to
entirely evaporate it at that temperature, is the total heat of
evaporation of the liquid for that temperature. It is the sum of the
heat of the liquid and the latent heat of evaporation.
To recapitulate, the heat added to a body is divided as follows:
Total heat = Heat to change the temperature + heat to overcome the
molecular cohesion + heat to overcome the external pressure
resisting an increase of volume of the body.
Where water is converted into steam, this total heat is divided as
follows:
Total heat = Heat to change the temperature of the water + heat to
separate the molecules of the water + heat to overcome
resistance to increase in volume of the steam,
= Heat of the liquid + internal latent heat + external
latent heat,
= Heat of the liquid + total latent heat of steam,
= Total heat of evaporation.
The steam tables given on pages 122 to 127 give the heat of the liquid
and the total latent heat through a wide range of temperatures.
Gases--When heat is added to gases there is no internal work done; hence
the total heat is that required to change the temperature plus that
required to do the external work. If the gas is not allowed to expand
but is preserved at constant volume, the entire heat added is that
required to change the temperature only.
Linear Expansion of Substances by Heat--To find the increase in the
length of a bar of any material due to an increase of temperature,
multiply the number of degrees of increase in temperature by the
coefficient of expansion for one degree and by the length of the bar.
Where the coefficient of expansion is given for 100 degrees, as in Table
6, the result should be divided by 100. The expansion of metals per one
degree rise of temperature increases slightly as high temperatures are
reached, but for all practical purposes it may be assumed to be constant
for a given metal.