[pure-silver] Re: Basic Chemistry


On Jun 15, 2008, at 5:15 AM, Peter Badcock wrote:


Nicholas,
Should T not be expressed in degrees Kelvin rather than degF ? This then takes into account the absolute nature of the temps in the system, rather than a temperature that has been scaled and offset (as are degF and degC). 

Peter
The key factor in the equations is the change in temperature for the solution and the water bath. If the correct units are used for heat capacity, it does not matter if you use F, C, K or Rankin. Q (heat) = change in temperature x mass x heat capacity (heat unit/mass x temp. unit)
In an ideal system, Q(lost) = Q (gained). Or for a cold bottle of solution going into a warm water bath, and they end up at a final temperature - - -
Q(lost) = mass of bath water x (final temp. - initial temp of bath) x heat capacity =
Q(gained = mass of solution x (final temp. - initial temp of solution) x heat capacity
Now we could really overkill the problem and include corrections for the heat capacity of the bath container, the heat capacity of the bottle, and the heat capacity of the solution(s) which will be slightly different from pure water. Also a term could be included to account for the loss of heat from the water bath to the room. 

Howard


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