﻿456 
  R. 
  G. 
  Van 
  Name 
  — 
  Temperature 
  Coefficient 
  

  

  K/<f>T, 
  the 
  reaction 
  velocity 
  divided 
  by 
  the 
  product 
  of 
  the 
  

   fluidity 
  and 
  the 
  absolute 
  temperature. 
  It 
  will 
  be 
  observed 
  

   that 
  this 
  ratio 
  is 
  very 
  nearly 
  constant, 
  its 
  maximum 
  variation 
  

   being 
  only 
  about 
  three 
  per 
  cent. 
  The 
  possible 
  significance 
  of 
  

   this 
  fact 
  will 
  be 
  considered 
  later. 
  

  

  Table 
  III. 
  

   Density, 
  Viscosity 
  and 
  Fluidity. 
  

  

  

  0° 
  

  

  15° 
  

  

  25° 
  

  

  35° 
  

  

  45° 
  

  

  55° 
  

  

  65° 
  

  

  d 
  

  

  1-0683 
  

  

  1-0663 
  

  

  1-0633 
  

  

  1-0594 
  

  

  1-0551 
  

  

  1-0499 
  

  

  1-0444 
  

  

  V 
  

  

  •01659 
  

  

  •01095 
  

  

  •00868 
  

  

  •00709 
  

  

  •00598 
  

  

  •00510 
  

  

  •00438 
  

  

  4> 
  

  

  K 
  

  

  60*3 
  

   10 
  & 
  22*6 
  

  

  91-3 
  

   22-3 
  

  

  115-2 
  

   22-2 
  

  

  141-1 
  

   22-0 
  

  

  167*4 
  

  

  22-2 
  

  

  196-2 
  

   22-2 
  

  

  228-3 
  

   21-9 
  

  

  The 
  fluidity 
  when 
  plotted 
  against 
  the 
  temperature 
  gives 
  a 
  

   curve 
  of 
  the 
  same 
  general 
  form 
  as 
  that 
  for 
  the 
  reaction 
  velocity 
  

   (fig. 
  1), 
  but 
  its 
  rate 
  of 
  increase 
  with 
  the 
  temperature 
  is 
  rela- 
  

   tively 
  slower. 
  This 
  fact 
  is 
  shown 
  in 
  a 
  different 
  way 
  in 
  Table 
  IV, 
  

   which 
  gives 
  the 
  temperature 
  coefficients 
  of 
  each 
  expressed 
  as 
  

   the 
  ratio 
  of 
  increase 
  for 
  every 
  10° 
  temperature 
  rise. 
  For 
  the 
  

   interval 
  0° 
  to 
  15° 
  the 
  value 
  of 
  this 
  coefficient 
  was 
  calculated 
  

   for 
  K 
  (and 
  similarly 
  for 
  <f>) 
  on 
  the 
  assumption 
  that 
  within 
  

   this 
  interval 
  d 
  InK/dT 
  = 
  constant. 
  Integrated, 
  this 
  gives 
  

   lor/ 
  }0 
  /{ 
  2 
  — 
  log 
  i0 
  K 
  1 
  = 
  A 
  (T^— 
  T 
  x 
  ) 
  (in 
  which 
  A 
  is 
  a 
  constant 
  whose 
  

   value 
  is 
  found 
  from 
  the 
  experimental 
  data), 
  and 
  hence 
  

  

  log 
  ^^ 
  = 
  10 
  A. 
  

  

  Table 
  IV. 
  

   Temperature 
  Coefficients 
  of 
  Reaction 
  Velocity 
  and 
  of 
  Fluidity. 
  

  

  0°-15° 
  15°-25° 
  25°-35° 
  35°-45° 
  45°-55° 
  55°-65° 
  

  

  *± 
  m 
  = 
  1-350 
  1-298 
  1-252 
  1-237 
  1'208 
  1'192 
  

  

  <^+io° 
  _ 
  1>261 
  1>225 
  1>]g6 
  1#172 
  1#163 
  

  

  <t>t 
  

  

  Discussion 
  of 
  Results. 
  

  

  The 
  absence 
  of 
  any 
  noticeable 
  irregularity 
  in 
  the 
  graph 
  of 
  

   the 
  reaction 
  velocity 
  in 
  fig. 
  1 
  is 
  an 
  indication 
  of 
  the 
  consistency 
  

   of 
  the 
  values 
  of 
  K, 
  and 
  their 
  probable 
  freedom 
  from 
  large 
  

   errors. 
  A 
  similar 
  series 
  of 
  measurements 
  has 
  been 
  made 
  by 
  

   Meyer 
  Wildermann* 
  of 
  the 
  rate 
  of 
  solution 
  of 
  benzoic 
  acid 
  

   in 
  water, 
  which 
  was 
  determined 
  at 
  five 
  temperatures 
  covering 
  

   the 
  range 
  between 
  1*5° 
  and 
  60°. 
  

  

  *Zeitschr. 
  phys. 
  Chem. 
  lxvi. 
  445, 
  1909. 
  

  

  