Page:Outlines of Physical Chemistry - 1899.djvu/67

 ��—

�Ckitical State

�Boiling point under atmo- spheric pressure

�Correspond- ing density

�Temperature l

�Pressure

�Density

�so.

01, 00,

CA

NO CH,

o,

CO

N, H,

�155°

140°

31°

10°

- 93°

- 82°

-118° -140° -146° -234°

�78*9 atmo. 93-0 „ 74-6 „ 51-0 „ 71-0 „ 550 „

50-0 „

39-0 „

330 „

15-0 „abt.

�r o-60 \

t 0-65 j

�-153-6° -164°

-181-5°

-190°

-194°

-238°

��The numbers obtained for the last six gases are from researches of Wroblewsky, Olczewsky, or Dewar.

The critical constants are also known for a large number of substances which are liquid at the ordinary temperature. The following are a few of these :

�� �Temperature

�Pressure

�C^joO (Ether)

�. 190°

�36*9 atmospheres

�CS*

�. 272°

�C*H 6 OH

�. 234°

�0,H 5 C1.

�. 183°

�O.H,. .

�. 281°

�CHOI,.

�. 260°

�HCOOCsHs.

�. 230°

�. 230°

�. 365°

��The determination of the Critical Temperature of a to 1 millimetre thick, a certain quantity of the substance is placed. The open end of the tube is drawn out to a capillary tube in such a way as to leave the completed

1 For the measurement of very low temperatures, see works on physics,

�� �