This SIR provides you with the opportunity to model the simple phenomena associated with the measurement of heat, using a representation of the simple foam-cup calorimeter.
You may measure the heat capacities of water and mercury directly, by electric heating. You may measure the heat capacities of various metals (including mercury) by immersing the hot metal in water. You determine the heat of melting of ice in a similar way. You may also determine the heats of neutralization of various acids and bases, including both strong and weak ones.
Heat Capacity of Water
It is determined by electric heating. A mass of water, chosen at random in the neighborhood of one kg, starts at a temperature just above 21° C, chosen at random by the computer.
Careful reading and calculation should give a result within a few tenths of a percent of 4.184 J/K/g.
Heat Capacity of Mercury
This is done in exactly the same way as the heat capacity of water. The mass of mercury, the voltage and the current are adjusted to use the four-degree temperature scale in a reasonable time. The heat capacity of mercury used in the simulation is 0.139 J/K/g.
Mercury in Water
Hot mercury, from a beaker of boiling water (there's a warning not to try this in the real world) is poured into water at about 21°. The masses of water and mercury are chosen so that the final temperature is within the four-degree scale of the thermometer. The temperature approaches its final value exponentially, in about 200 "seconds". You should wait for at least half of this time to get a stable reading.
Metals in Water
You may determine the heat capacities of any of 10 metals, in the same way as theat of mercury. You may, if you wish, discover the law of Dulong and Petit.
Melting Ice
A lump of ice at 0° is dumped into water near 25°; from the masses and the temperature change on melting you may deduce the heat of melting of ice.
Heat of Neutralization
In this simulation, you may choose any one of 12 acid-base pairs. You start with one litre of each, both at 25.00°. After they are mixed, the temperature rises to a final value, from which you calculate the molar heat of neutralization.
You may choose any of five concentrations, from 0.1 M to 0.5 M, for each starting solution, to demonstrate that the heat of reaction is proportion to the amount of reaction, not the amount of reactant.
Strong and weak acids and bases are included, so you may show that the heats of neutralization of all strong acid-base pairs are identical; those of weak acids or bases vary. By judicious choice of reaction you may demonstrate the evidence for complete dissociation of strong acids and bases, and partial dissociation of weak ones.
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Updated July 25, 2000