﻿68 
  Mixter 
  — 
  Heat 
  of 
  Formation 
  of 
  the 
  

  

  Heateffect 
  6760 
  9136 
  9095 
  c 
  

  

  " 
  " 
  of 
  sulphur 
  2620 
  2620 
  

  

  " 
  " 
  " 
  iron 
  ... 
  50 
  50 
  50 
  

  

  " 
  " 
  "CdS.. 
  6710 
  6466 
  6425 
  

  

  " 
  " 
  " 
  1 
  gram 
  CdS 
  1227 
  J241 
  1231 
  

  

  The 
  average 
  is 
  1233 
  c 
  for 
  the 
  heat 
  of 
  reaction 
  of 
  1 
  gram 
  of 
  

   cadmium 
  sulphide 
  with 
  sodium 
  peroxide. 
  For 
  1 
  gram 
  mole- 
  

   cule 
  it 
  is 
  178,100 
  c 
  . 
  

  

  For 
  the 
  heat 
  of 
  formation 
  of 
  cadmium 
  sulphide 
  we 
  have 
  

  

  Cd 
  + 
  Na 
  2 
  2 
  - 
  = 
  44,100 
  c 
  

  

  S 
  + 
  3Na 
  2 
  2 
  = 
  168,000 
  

  

  Cd 
  + 
  S 
  + 
  4Na 
  2 
  2 
  ._ 
  = 
  212,100 
  

  

  CdS 
  + 
  4Na 
  2 
  2 
  _ 
  = 
  178,100 
  

  

  Cd 
  + 
  S(rhombic) 
  = 
  CdS(crys.) 
  = 
  34,000 
  

  

  Summary. 
  

  

  Cd 
  + 
  Na 
  2 
  2 
  = 
  44,100 
  c 
  * 
  

  

  Na 
  2 
  + 
  O 
  = 
  19,400 
  

  

  Cd 
  + 
  O 
  + 
  Na 
  2 
  = 
  63,500 
  

  

  CdO 
  4- 
  Na,0 
  = 
  6,500 
  * 
  approx. 
  

  

  Cd 
  + 
  O 
  = 
  CdO(amor.) 
  = 
  57.000 
  \ 
  « 
  

  

  Cd 
  + 
  O 
  = 
  CdO(mostlv 
  crys.) 
  = 
  63,000 
  * 
  

  

  Cd 
  + 
  S(rhombic) 
  = 
  CdS(crys.)__ 
  . 
  = 
  34,000 
  f 
  

  

  Thomson 
  found 
  Cd, 
  O, 
  H 
  2 
  = 
  65,800 
  c 
  , 
  and 
  Cd, 
  S, 
  H 
  2 
  = 
  

   32,350 
  c 
  . 
  

  

  Note 
  on 
  Ferrous 
  Oxide. 
  

  

  A 
  quantity 
  of 
  ferrous 
  oxide 
  was 
  needed 
  and 
  it 
  appeared 
  

   from 
  the 
  statements 
  in 
  Moissan's 
  Traite 
  de 
  Chimie 
  best 
  

   to 
  make 
  it 
  from 
  ferrous 
  oxalate. 
  In 
  the 
  first 
  attempt 
  the 
  

   oxalate 
  was 
  heated 
  rapidly 
  to 
  a 
  red 
  heat 
  in 
  a 
  bulb 
  with 
  a 
  

   narrow 
  neck, 
  the 
  end 
  of 
  which 
  passed 
  into 
  water. 
  After 
  gas 
  

   ceased 
  to 
  come 
  off 
  the 
  neck 
  was 
  closed 
  and 
  the 
  bulb 
  allowed 
  

   to 
  cool. 
  The 
  product 
  was 
  found 
  to 
  have 
  very 
  nearly 
  the 
  per 
  

   cent 
  of 
  iron 
  in 
  ferrous 
  oxide. 
  It 
  was, 
  however, 
  a 
  mixture 
  of 
  

   metallic 
  iron, 
  ferrous 
  and 
  ferric 
  oxides 
  and 
  contained 
  sufficient 
  

   carbon 
  to 
  render 
  it 
  useless 
  for 
  the 
  calorimetric 
  work. 
  

  

  When 
  ferrous 
  oxalate 
  is 
  heated 
  rapidly 
  the 
  reduction 
  product 
  

   first 
  formed 
  from 
  the 
  oxalate 
  in 
  contact 
  with 
  the 
  hot 
  sides 
  of 
  

   the 
  containing 
  vessel 
  is 
  exposed 
  to 
  the 
  action 
  of 
  the 
  oxides 
  of 
  

   carbon 
  and 
  water 
  vapor 
  from 
  the 
  decomposing 
  oxalate. 
  Under 
  

   these 
  conditions 
  carbon 
  separates, 
  since, 
  as 
  is 
  well 
  known, 
  

   carbon 
  monoxide 
  at 
  1000° 
  dissociates 
  thus 
  : 
  

   2CO 
  -^i 
  C0 
  2 
  -I- 
  C. 
  

  

  To 
  avoid 
  separation 
  of 
  carbon 
  or 
  formation 
  of 
  iron 
  carbide 
  

   ferrous 
  oxalate 
  was 
  heated 
  in 
  a 
  current 
  of 
  pure 
  dry 
  nitrogen. 
  

   The 
  temperature 
  was 
  raised 
  gradually 
  and 
  at 
  the 
  end 
  of 
  four 
  

   * 
  Experimental 
  result. 
  f 
  Derived 
  result. 
  

  

  