Budowa i działanie kalorymetru

1. What is the calorimeter and what is it used for?

The calorimetercalorimetercalorimeter is a device used to analyse the heat flow between the bodies in conditions which prevent heat exchange with the environment.

2. Present the construction of the calorimeter.

Description of the construction of the calorimetercalorimetercalorimeter.

• In the outer cupouter cupouter cup there is a coaster which thermally isolates the inner cupinner cupinner cup from the environment.

• The inner cup is placed on the insulating coaster.

• Immobile air surrounds the inner cup which functions as a perfect insulator.

• In order to increase the insulation of the substance which is in the inner cup, it is covered on top with a thermally insulating lid.

• The thermometerthermometerthermometer and the stirrerstirrerstirrer pass through the lid to equalise the temperatures inside the entire internal cup.

3. Present the principle of operation of the calorimetercalorimetercalorimeter.

We usually pour a certain amount of liquid into the inner cupinner cupinner cup. We measure its initial temperature. Then we put a specific body into the inner cup. We close the calorimeter tightly and use the stirrerstirrerstirrer. We note the highest temperature indicated by the thermometerthermometerthermometer. Using the heat balanceheat balanceheat balance, we determine the unknown value.

4. Provide examples of the application of the calorimeter.

It is generally accepted that calorimeters are laboratory devices designed mainly to determine the heat of combustion and to calculate the calorific value of different solid, liquid and mixed substances. This is a myth, because these are much more universal laboratory devices which allow not only to obtain information about the physicochemical properties of the tested substances, but also to creatively use this knowledge in industrial applications. The possibility of conducting various innovative research at universities and research institutes should be also mentioned. The calorimetric bomb used in the calorimetercalorimetercalorimeter allows to conduct different tests in conditions of higher pressure and in the atmosphere of various gases such as: oxygen, nitrogen, argon, hydrogen, etc. or in the air. Due to temperature analysis, it is also possible to determine the change in the properties of the tested substances not only as a result of combustion, but also physicochemical phenomena of various origin, including biological ones.

Summary

• The calorimeter - a laboratory device for measuring the heat emitted or consumed during chemical and physical processes.

• The simplest calorimeter, the so‑called „school calorimeter”, is a device which measures changes in temperature during the process in which the sample mass of the body is precisely defined. To eliminate accidental heat exchange with the environment, the system must be well insulated. This kind of calorimeter is effective when the temperature changes of system are large and it can only be used for liquid systems.

• At schools, calorimeters, which are made of aluminum, are most often used. In contrast, laboratories use well insulated calorimeters of very high accuracy which often connected to the computer.

Exercises

Glossary

Keywords

calorimetercalorimetercalorimeter

inner cupinner cupinner cup

stirrerstirrerstirrer

thermal isolationthermal isolationthermal isolation

thermometerthermometerthermometer