W. G. Mixter — Polymerisation of Oxides. 25 



Table I 



12 3 4 5 6 



CaS0 4 (a) 4026 4-865 5-166 ■ 



CaS0 4 .2H 2 (b) 3-085 3-000 5"233 g 



S 1-000 1-000 1-000 1-000 



Lampblack (C) 1-290 1274 



Na»0 2 13-5 14- 24- 19- 18' 22- 



Water equiv. of system 4122 4056 4112 4138 4125 4166 



Temperature interval T612 1-709 3-745 1*777 1-764 4076° 



Oxygen set free 



Heat effect... 6645 6932 .5400 7353 7277 16981 cal 



" " ofS. -5300 -5300 -5300 -5300 



" "C--_ -13722 13551 



" " " Fe -40 -42 -40 -40 -40 -40 



" " a (c). 1305 1592 1638 



" "b(dj. 2013 1937 3390 



" "lg. of a- 324 327 317 



a 



" " " " b^ .... 653 646 648 



b 



oxide gives no heat effect in fusion with sodium peroxide and 

 sulphur, hence the heat effect of CaS0 4 is from the reaction of 

 this compound with sodium oxide as shown in equation 1 be- 

 low. The mean of 4, 5 and 6 for CaS0 4 .2H 2 is 649 cal., or 

 111 6 Cal. for 1 gram molecule. 



The calculated heat effect of 1 gram of sulphur reacting 

 with sodium peroxide is 5300 cal. and this value is used because 

 Thomsen's values are adopted in the equations 1, 2, 3 and 4, 

 given later. The lampblack used was of the lot used in pre- 

 vious work.f 



(1) (Ca + S + 40) + (2Na + O) = (2Na + S + 40) + (Ca + O) 

 332-4 100-3 3286 145. 



+ 40-9 Cal. 



The experimental result is 437 Cal. Including sulphur and 

 sodium peroxide in the calculation, we have 



S + 3 (2Na + 20) + (Ca + S + 40) = 2(2Na + S + 40) + 

 359-4 332-4 657'2 



(Ca + O) + (2Na + O) + 210-7 Cal. 

 145 100-3 



The calculated heat of the reaction between sulphur and sodium 

 peroxide is 169-8 Cal., and adding this to 43 -7 gives 213-5 Cal. 

 for the observed heat effect. For the hydrous sulphate we 

 have 



f Loc. cit. 



