Part 9 (1/2)

The specific heat of athe specific heat of each constituent gas by the percentage by weight of that gas in thethe suas whose coht is CO_{2}, 13 per cent; CO, 04 per cent; O, 8 per cent; N, 786 per cent, is found as follows:

CO_{2} : 13 0217 = 2821 CO : 04 02479 = 009916 O : 8 02175 = 174000 N : 786 02438 = 1916268 -------- 1000 2382284

and 238228 100 = 0238 = specific heat of the gas

The specific heats of various solids, liquids and gases are given in Table 4

Sensible Heat--The heat utilized in raising the te the te point, is termed sensible heat In the case of water, the sensible heat required to raise its te point corresponding to the pressure under which ebullition occurs, is termed the heat of the liquid

Latent Heat--Latent heat is the heat which apparently disappears in producing so its te temperature, the ice will melt but its te the condition of the ice is the latent heat and in this particular case is known as the latent heat of fusion If heat be added to water at 212 degrees under atmospheric pressure, the water will not become hotter but will be evaporated into stearees The heat so utilized is called the latent heat of evaporation and is the heat which apparently disappears in causing the substance to pass froaseous state

TABLE 4

SPECIFIC HEATS OF VARIOUS SUBSTANCES +--------------------------------------------------------------------+ | SOLIDS | +-------------------------------+----------------+-------------------+ | | Terees | Specific | | | Fahrenheit | Heat | +-------------------------------+----------------+-------------------+ | Copper | 59-460 | 0951 | | Gold | 32-212 | 0316 | | Wrought Iron | 59-212 | 1152 | | Cast Iron | 68-212 | 1189 | | Steel (soft) | 68-208 | 1175 | | Steel (hard) | 68-208 | 1165 | | Zinc | 32-212 | 0935 | | Brass (yellow) | 32 | 0883 | | Glass (normal ther 16{III}) | 66-212 | 1988 | | Lead | 59 | 0299 | | Platinum | 32-212 | 0323 | | Silver | 32-212 | 0559 | | Tin | -105-64 | 0518 | | Ice | | 5040 | | Sulphur (newly fused) | | 2025 | +-------------------------------+----------------+-------------------+ | LIQUIDS | +-------------------------------+----------------+-------------------+ | | Terees | Specific | | | Fahrenheit | Heat | +-------------------------------+----------------+-------------------+ | Water[3] | 59 | 10000 | | Alcohol | 32 | 5475 | | | 176 | 7694 | | Mercury | 32 | 03346 | | Benzol | 50 | 4066 | | | 122 | 4502 | | Glycerine | 59-102 | 576 | | Lead (Melted) | to 360 | 0410 | | Sulphur (melted) | 246-297 | 2350 | | Tin (r 10043) | 64 | 980 | | Sea Water (sp gr 10463) | 64 | 903 | | Oil of Turpentine | 32 | 411 | | Petroleum | 64-210 | 498 | | Sulphuric Acid | 68-133 | 3363 | +-------------------------------+----------------+-------------------+ | GASES | +--------------------------+---------------+--------------+----------+ | | | Specific | Specific | | | Terees | Constant | Constant | | | Fahrenheit | Pressure | Volume | +--------------------------+---------------+--------------+----------+ | Air | 32-392 | 2375 | 1693 | | Oxygen | 44-405 | 2175 | 1553 | | Nitrogen | 32-392 | 2438 | 1729 | | Hydrogen | 54-388 | 34090 | 24141 | | Superheated Steam | | See table 25 | | | Carbon Monoxide | 41-208 | 2425 | 1728 | | Carbon Dioxide | 52-417 | 2169 | 1535 | | Methane | 64-406 | 5929 | 4505 | | Blast Fur Gas (approx) || 2277 || | Flue gas (approx) || 2400 || +--------------------------+---------------+--------------+----------+

Latent heat is not lost, but reappears whenever the substances pass through a reverse cycle, froaseous to a liquid, or from a liquid to a solid state It may, therefore, be defined as stated, as the heat which apparently disappears, or is lost to thermometric measure changed Latent heat is expended in perfor the molecular cohesion of the particles of the substance and in overcoe of volume of the heated body Latent heat of evaporation, therefore, may be said to consist of internal and external heat, the for theto stea any resistance to the increase of its volu a pound of water at 212 degrees to stearees, 8976 B t u are expended as internal latent heat and 728 B t u as external latent heat For a ht about in water by sensible and latent heat, the reader is again referred to the chapter on ”The Theory of Stea”

Ebullition--The te point, may be defined as the temperature which exists where the addition of heat to the liquid no longer increases its te absorbed or utilized in converting the liquid into vapor

This temperature is dependent upon the pressure under which the liquid is evaporated, being higher as the pressure is greater

TABLE 5

BOILING POINTS AT ATMOSPHERIC PRESSURE

+---------------------+--------------+ | | Degrees | | | Fahrenheit | +---------------------+--------------+ | Ammonia | 140 | | Bromine | 145 | | Alcohol | 173 | | Benzine | 212 | | Water | 212 | | Average Sea Water | 2132 | | Saturated Brine | 226 | | Mercury | 680 | +---------------------+--------------+

Total Heat of Evaporation--The quantity of heat required to raise a unit of any liquid froiven 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 overco 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 steaiven on pages 122 to 127 give the heat of the liquid and the total latent heat through a wide range of teases there is no internal work done; hence the total heat is that required to change the teas is not allowed to expand but is preserved at constant volue 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 terees of increase in teree 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 htly as high temperatures are reached, but for all practical purposes it iven metal

TABLE 6

LINEAL EXPANSION OF SOLIDS AT ORDINARY TEMPERATURES