2006-06-23 01:32:13 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
There are several techniques for measuring heat on small lab vessels. The only practical solution for larger systems (above 1 litre) however is to measure the heat gained or lost by the heating/cooling medium The idea is that you measure the mass flow and temperature change of cooling/heating fluid (plus corrections for heat loses and temperature changes). The problem with this method however is that it does not work well with tradition cooling systems. To measure heat on large systems, you need to use a cooling jacket which operates at constant flux.
2006-06-23 02:30:52 · answer #1 · answered by A B 1 · 2⤊ 1⤋
You will need to know the reaction taking place. You will also need to know the starting and ending concentrations, the heat capacities of each component (including solvent) and the heat transfer profile (either temp v time for reactor or heat exchanger inputs/outputs over time). Also, the potential for phase changes in the system (solvent evap, etc) and side reactions (really complicates things).
From the heat data, you can calculate the amount of heat moving into/out of the system. From the heat capacity data, you can figure out the amount of heat associated with the components being heated/cooled/evaporated/condensed in the system (you will need to assume a reaction order, and time average the component mix). the residual heat should be close to that associated with the heat of reaction. Figure out the moles reacted and there you go.
Oh yeah, I'm sure you have a well insulated vessel, too. Right?
Best to look up the reaction or get a calorimeter.
2006-06-23 09:28:55 · answer #2 · answered by scott_d_webb 3 · 0⤊ 0⤋
IF there was only a single reaction taking place then you could figure it out from the temperature change and the output of the reactor
I'm not an experimental person though, I just figure out which reactions are taking place and lookup values in a book or a database
2006-06-23 08:39:53 · answer #3 · answered by Mike 5 · 0⤊ 0⤋
a bomb calorimeter is the usual method. depends on how large of a scale you are talking about though.
2006-06-23 12:45:50 · answer #4 · answered by Joe 2 · 0⤊ 0⤋
If it burns you, then it's hot.
2006-06-23 08:37:31 · answer #5 · answered by Captain Eyewash 5 · 0⤊ 0⤋
with a thermometer??
2006-06-23 09:41:14 · answer #6 · answered by Melissa Me 7 · 0⤊ 0⤋