444 FooTE AND mohler: ionization 



V2(Cl2) + Z^Cl = (CI) 



(H) + 7h = (H) + 



(Cl)j- .Ed = (Cl)- 

 Adding : 



(HCl) = Qhci + Dn-h Del + Ju - ^ci = (H)+ + (Cl)- 

 /hci = Qhci -\- Dn -{- Dci + /h — ^ci (14) 



= 22 + 45 + 56 + 312 - 119 

 = 316 kg. cal. - 13.7 volts 

 Value observed by Foote and Mohler^" = 14.0 volts. 

 Similarly 



JhBv = QhBv + Du + Dbt + /h - £^Br (iS) 



= 12 + 45 + 23 + 312 - 84 

 = 308 kg. cal. o 13 .3 volts 

 Similarly 



7hi =~QIT+ Pn + A + /h - £1 (16) 



= ..^ +451+ 18 + 312 - 77 

 = 299 kg. cal. <> 12 .9 volts 



Hydrogen Sulphide. —On the assumption that hydrogen sul- 

 phide may be ionized by dissociation, Bom and Bommann^^ 

 have computed the ionization potential to be about 31 volts. 

 The thermochemical relations are as follows: 



(HaS) + Q(H.s) = (H2) + [S] 

 (Ho) + 2Dn = 2(H) 

 2(H) + 27h = 2(H) + 



[S] + 5s = (S) 



(S) - £s = (S)- 



Adding : 



(H2S) + Qh.S + 2Dh + 2 J,, + 5s - Es = 2(H)+ + (S) — 



/h^S = QhjS + 2L>H + 27h + 5s - £s 

 = 5+90 + 624 + 59-50 



= 728 kg. cal. ^31.5 volts 

 The above examples suffice to show that an investigation of 

 the ionization potential of vapors of various compounds is of 

 exceedingly great interest from the thermochemical standpoint. 



10 Loc. cit. 



" Zeit. f. Physik 1: 250. 1920. 



