[pure-silver] Re: Basic Chemistry
- From: "Peter Badcock" <peter.badcock@xxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sun, 15 Jun 2008 21:15:50 +1000
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
2008/6/13 Nicholas O. Lindan <nolindan@xxxxxxxxxxxxx>:
> <eroustom@xxxxxxxxxxx>
>
>> I use a hot bath to put my bottles of working solutions in to bring them
>> to temp.
>>
>
> If my solutions are all at basement temp of 60 to 64F, what should the hot
>> bath be at to bring everything to 68-70F. 1 Liter glass bottles (usually
>> full). 6 Liter tub of water.
>>
>
> Well, in typical high-school chemistry fashion:
>
> Neglecting the thermal effects of the bottles
> Assuming everything is in a perfectly insulating container
>
> Aq + Br + Cs = T * (A + B + C)
>
> A, B, C ... are the volumes
> q, r, s ... are their initial temperatures
> T is the final temperature
>
> Which should be sort of obvious, if you
> think about it.
>
> For a bottle (vol. A, temp q) in a water bath (vol. B, temp r), the
> temperature r at the start to reach a final temperature T should be
>
> r = [(A / B) * (T - q)] + T
>
> or: r = [(the ratio of the volumes)
> times (the difference in temperatures)]
> plus
> the final temperature
> Not a bad thing to tape to the wall.
>
> For one bottle:
>
> The volume ratio is 1:6
> The temperature difference is 68F - 62F = 6F
> The final temperature is to be 68F
>
> r = 1/6 * 6F + 68F
> = 70F water bath
>
> For 3 bottles the volume ratio is 3:6,
> the student can calculate the temperature.
> Quiz next Tuesday.
>
> In real life things will be different: you have a flow of
> heat to the air, the water bath container, the lab bench,
> the glass bottle, and you are loosing heat to evaporation, gaining heat
> from your stirring, loosing heat to warming the chemicals in the bottle
> (don't forget to use the
> volume of the water _before_ the chemicals were mixed in)...
>
> Experiment and making a table will be the fastest and most accurate method.
> Which is also sort of obvious.
>
> ==
> Nicholas O. Lindan
> Cleveland Engineering Design, LLC
> Cleveland, Ohio 44121
>
>
> =============================================================================================================
> To unsubscribe from this list, go to www.freelists.org and logon to your
> account (the same e-mail address and password you set-up when you
> subscribed,) and unsubscribe from there.
>
Other related posts:
