﻿66 
  

  

  Mixter 
  — 
  Heat 
  of 
  Formation 
  of 
  the 
  

  

  dust 
  remaining. 
  This 
  was 
  collected 
  on 
  a 
  Gooch 
  filter, 
  heated 
  

   and 
  its 
  weight 
  added 
  to 
  that 
  in 
  the 
  crucible. 
  The 
  following 
  

   are 
  the 
  results 
  : 
  

  

  Cadmium 
  (a) 
  21*820 
  23*047 
  27*107 
  grams 
  

  

  Weight 
  of 
  product 
  (£)._ 
  24*355 
  25*684 
  30*170 
  

  

  " 
  " 
  2 
  combined, 
  b 
  — 
  a(c). 
  2*535 
  2*637 
  3*063 
  

  

  Cotton 
  _ 
  0*218 
  0*150 
  0*137 
  

  

  Weight 
  of 
  2 
  in 
  bomb 
  8*5 
  10*5 
  11* 
  

  

  Water 
  equivalent 
  of 
  system 
  3656 
  3632 
  3635 
  

  

  Temperature 
  interval 
  2*951 
  3*053 
  3*600° 
  

  

  Heat 
  effect 
  _. 
  10789 
  11088 
  13086° 
  

  

  ". 
  " 
  of 
  cotton 
  882 
  606 
  544 
  

  

  " 
  " 
  " 
  c(d) 
  9908 
  10482 
  12542 
  

  

  d 
  

   A 
  " 
  " 
  1 
  gram 
  of 
  O- 
  .. 
  3909 
  3975 
  4094 
  

  

  Part 
  of 
  the 
  product 
  of 
  a 
  combustion 
  was 
  reddish 
  brown 
  cad- 
  

   mium 
  oxide 
  on 
  the 
  sides 
  of 
  the 
  bomb 
  and 
  a 
  considerable 
  por- 
  

   tion 
  was 
  a 
  black 
  sintered 
  mass, 
  fused 
  on 
  top 
  and 
  showing 
  some 
  

   crystals 
  beneath. 
  The 
  atomic 
  ratios 
  of 
  the 
  cadmium 
  taken 
  to 
  

   the 
  oxygen 
  combined 
  are 
  respectively 
  1*22, 
  1*25 
  and 
  1*26 
  to 
  1. 
  

   That 
  is, 
  1/5 
  of 
  the 
  cadmium 
  had 
  not 
  burned. 
  Free 
  metal 
  was 
  

   not 
  visible 
  in 
  the 
  sintered 
  mass, 
  but 
  the 
  later 
  left 
  some 
  metal 
  

   when 
  treated 
  with 
  hydrochloric 
  acid. 
  It 
  is 
  not 
  probable 
  that 
  

   cadmium 
  suboxide 
  was 
  present 
  since 
  it 
  breaks 
  up 
  into 
  oxide 
  

   and 
  metal 
  when 
  heated. 
  For 
  the 
  effect 
  of 
  heat 
  on 
  cadmium 
  

   oxide 
  see 
  note 
  on 
  p. 
  69. 
  

  

  The 
  average 
  heat 
  effect 
  of 
  1 
  gram 
  of 
  oxygen 
  found 
  is 
  3993 
  c 
  

   and 
  for 
  1 
  gram 
  atom 
  combining 
  with 
  cadmium 
  to 
  form 
  crystal- 
  

   line 
  oxide 
  and 
  a 
  little 
  amorphous 
  oxide 
  the 
  result 
  is 
  63,900 
  c 
  . 
  

  

  Cadmium 
  Oxide. 
  — 
  Cadmium 
  carbonate 
  was 
  precipitated 
  

   from 
  a 
  boiling 
  solution 
  of 
  pure 
  sulphate 
  by 
  a 
  slight 
  excess 
  of 
  

   sodium 
  carbonate. 
  It 
  was 
  washed, 
  dried 
  and 
  heated 
  to 
  a 
  

   bright 
  red 
  heat. 
  The 
  portion 
  of 
  the 
  oxide 
  taken 
  for 
  a 
  calori- 
  

   metric 
  experiment 
  was 
  heated 
  in 
  a 
  platinum 
  crucible 
  to 
  red- 
  

   ness. 
  The 
  crucible 
  and 
  contents 
  were 
  allowed 
  to 
  cool 
  in 
  a 
  

   desiccator, 
  weighed 
  and 
  the 
  oxide 
  at 
  once 
  transferred 
  to 
  the 
  

   bomb. 
  

  

  The 
  following 
  are 
  the 
  results 
  with 
  cadmium 
  oxide 
  : 
  

  

  Cadmium 
  oxide 
  (a) 
  5*840 
  6*372 
  grams 
  

  

  Sulphur 
  2*344 
  2*095 
  

  

  Sodium 
  peroxide. 
  _ 
  27* 
  27* 
  

  

  Water 
  equivalent 
  of 
  system 
  _ 
  4130 
  4232 
  

  

  Temperature 
  interval 
  _ 
  3*057 
  2*677° 
  

  

  