The time course of the heat effects in rapid chemical changes. Part I.—Apparatus and methods

Abstract

Continuous flow calorimetry has now been in use for upwards of 30 years, having been adopted in the first instance by Callendar and Barnes for determination both of the specific heat of water at various temperatures and of J, the mechanical equivalent of heat. The principle of the method is simply that the fluid, upon which calorimetric observations are to be made, is driven continuously through a tube, and at a definite point or part of the tube acquires a certain amount of heat (by electric heating, mixture with another fluid or otherwise). The amount of heat in question is determined by noting the temperature of the moving fluid just before it reaches the heating zone, the temperature of the moving fluid just after it has passed the heating zone and M, the volume of fluid moving through the tube per second. Then the amount of heat received by the fluid per second = Mρσ(θ 1 - θ 2 ) where ρ = density and a = specific heat of the fluid, omitting the slight cor­rections for the exchange of heat between the fluid and its surroundings as it travels between the two points of the tube, at which the temperature observa­tions are made.