H Veeder <[email protected]> wrote: >From the point of the calorimeter heat is not absorbed since no heat > vanishes. >
The energy does vanish! You put in X amount of electricity but only a fraction of X comes out. The rest goes into changing the chemical structure of the egg you are cooking, or the hydride you are forming (or whatever endothermic process is happening). > Like all measuring instruments a calorimeter is incapable of doing > anything other than it was designed to do and that consists in detecting > changes or lack of changes in heat content. Whether or not the data it > supplies represents exothermic or endothermic reactions requires further > interpretation based on additional knowledge. > "Endothermic" means the reaction absorbs energy. It outputs less than you put in. Obviously the calorimeter tells you that is happening. It can do that for the same reason it tells you that a chemical or nuclear reaction produces *more* than you put in. It does not require any interpretation or additional knowledge. That's like saying you need additional knowledge to be sure you have gained weight when your bathroom scale says you are 10 lbs heavier. No, you don't. The numbers are right there. > We can rule out this scenario for most cold fusion experiments, including >> McKubre's, because the periods when there is no heat are shorter than the >> continuous periods when there is heat. So the deficit would have to be as >> large or larger than the positive heat release. >> >> >> > > Whether or not an excess heat event is long or short is relative to when > the accounting period begins. > Does he include the time and energy spent loading? > The balance is zero during loading, except the initial phase when the palladium loads a significant amount of hydrogen. As I said, there are no quiescent periods long enough to store energy below the level of detection, and during the exothermic periods far more energy comes out than any mechanism can store in chemical reactions. > The calorimeter doesn't tell you there is a "deficit". > Of course it does! That's what it is for. > The only thing it tells you is how much and how quickly the heat content > of the system changes.The "deficit" is an *interpretation* of this raw > data. > Since you measure input electricity as well as output heat, you can see there is a balance, a deficit or an excess. To repeat, unless the temperature falls a calorimeter by itself cannot tell > you if an endothermic process has occurred. > No, the temperature does not need to fall. When it does not rise as much as it does when all input energy converts to heat, you know you have an endothermic reaction. Imagine you shovel 20 kg of coal into a 1 kg container. You then weigh the container. If it weighs 25 kg you have magically created excess mass. It weighs only 15 kg you have destroyed mass. That cannot happen with mass but it happens all the time with energy going into a system, for example when you cook eggs, charge up a battery, or strike a match (endothermic, endothermic, exothermic). The whole point of a calorimeter is to measure the energy balance in such reactions. > You need additional information to interpret the meaning of the lack of > rise in temperature . > Well, you have to know how the temperature reflects the power, but that is the same knowledge you need to characterize an exothermic reaction. I suggest you read a book about calorimetry, such as Hemminger and Hohne, which I spent a few hours cribbing from yesterday. - Jed
