Page:Outlines of Physical Chemistry - 1899.djvu/191

 HEAT OF FORMATION

��Aromatic Substances

��^T

� �Heat of Formation

�Heat

�Name

�Formula

� � � � �of Com-

� � �Gas

�Liquid

�Solid

�Dis- solved

�bustion

� � � � � � �Cal.

�Benzene.

�C 6 H 6 j

i

�-11-3*

�- 4-1*

�Naphthalene.

�-22-8*

�Phenol

�36-8*

�Resorcin.

�CeHgOg

� � �89-4*

�Hydroquinone.

�id.

� � �87-3*

�Pyrocatechin.

�id.

� � �87-6*

�Gresol, ortho-.

� � �56-3*

�„ para-.

�id. ,

� � �55-1*

�„ meta-.

�id. i

�55-7*

�Benzoic acid.

�C r H 6 2 !

�94-2*

�Benzaldehyde.

�C 7 H 6 ;

� �25-4*

�•

�Benzyl alcohol.

� �40-8*

�Methyl benzoate

� �86-8*

�Salicylic acid.

�C 7 H 6 s

� � �1321*

�Paraoxybenzoic

�i

� � � � �i

�acid

�id.

� � �141-2*

�Metaoxybenzoic

� � � � � � �acid

�id. !

� � �138-1*

�Aniline

�C 6 H 7 N

� �-11-2*

�Azobenzene

� �- 79-2*

�Nitrobenzene.

� �51*

�Meta-dinitroben-

� � � � � � �zene

� � �6-8*

�Phenylhydrazine

� �36 *

�Terebenthene.

�4-2*

�Camphor.

�C 10 H 18 O

� � �80-3*

��The asterisk (*) denotes the heat of formation directly calculated from the heat of combustion.

��For the higher homologues of the aromatic substances the heats of combustion can be obtained sufficiently closely by adding 155 Cal. for each additional CH 2 group. As for the fatty compounds, so in general with the aromatic sub- stances, the heat of combustion is only strongly influenced by isomerism in so far as it affects the linkages which exist between the carbon atoms (single, double, or triple bonds).

�� �