Dalton's Law

Material	Specific Heat      CP                CV		R
Air ...................................	74	.17	53.34
R-717 (Ammonia)   . . . .	,51	.35	123.24
R-744 (Carbon Dioxide)	.22	.17	38.82
Ether................................	48	.45	23.11
Oxygen ...........................	22	.16	48.55
Alcohol ...........................	45	.40	41.55
Water Vapor ...................	480	.37	83.23

Fig. 1-23. A table of gas values (constants) for some
common substances.

Dalton's Law of partial pressures is the foundation of the principle of operation of one of the absorption type refrigerators. The law may be stated as follows:

The total pressure of a confined mix­ture of gases is the sum of the partial pressures of each of the gases in the mixture." The total pressure of the air in a compressed air cylinder is the sum of the oxygen gas, the nitrogen gas, the carbon dioxide gas, and the water vapor pressure.

The law further explains that each gas behaves as if it occupies the space ALONE. This behavior also explains why water will evaporate from a floor after a scrubbing. The water vapor pressure is so low in the air that the water will turn to water vapor (very slowly of course) at temperatures of 70 F. down to freezing.