Calorimeter A device used to measure the

Bomb calorimeter A device used to measure the heat transfer between system and surroundings at constant volume. 

You measure the heat of reaction in a calorimeter, a device used to measure the heat absorbed or evolved during a physical or chemical change. The device can be as simple as the apparatus sketched in Figure 6.12, which consists of an insulated container (for example, a pair of polystyrene coffee cups) with a thamometCT. More elaborate calorimeters arc employed when precise measurements are needed for research, although the basic idea remains the same—to measure temperature changes under controlled circumstances and relate these temperature changes to heat. 

Calorimeter a device used to measure the heat absorbed or evolved during a physical or chemical change. (6.6)... 

A calorimeter is a device used to measure the work that would have to be done under adiabatic conditions to bring about a change from state 1 to state 2 for which we wish to measure AU= U -U This work is generally done by passing a known constant electric current 3 for a known time t through a known resistance R embedded in the calorimeter, and is denoted by where... 

A calorimeter Is a device used to measure heat flows that accompany chemical processes. The basic features of a calorimeter include an Insulated container and a thermometer that monitors the temperature of the calorimeter. A block diagram of a calorimeter appears in Figure 6-15. In a calorimetry experiment, a chemical reaction takes place within the calorimeter, resulting in a heat flow between the chemicals and the calorimeter. The temperature of the calorimeter rises or falls in response to this heat flow. 

The value of AH can be determined experimentally by measuring the heat flow accompanying a reaction at constant pressure. Typically, we can determine the magnitude of the heat flow by measuring the magnitude of the temperature change the heat flow produces. The measurement of heat flow is calorimetry a device used to measure heat flow is a calorimeter. 

Boiling point elevation (ATb) Increase in the boiling point caused by addition of a nonvolatile solute, 269-271 Bomb calorimeter Device used to measure heat flow, in which a reaction is carried out within a sealed metal container, 202-203... 

The amount of heat can be measured in a device called a calorimeter. A calorimeter is a container with insulated walls. The insulation prevents a rapid heat exchange between the contents of the calorimeter and the surroundings. In the closed environment of the system, there is no loss or gain of heat. Since the change in temperature of the contents of the calorimeter is used to measure the magnitude of the heat flow, a thermometer is included with the calorimeter. 

The typical way to measure the heat released during a reaction is to measure the temperature change of the surroundings. This can be accomplished by using a device known as a calorimeter. The purpose of a calorimeter is to create a closed system in which to perform the reaction. The closed system allows the heat to be transferred entirely from the reactants to the surroundings without interference from the outside environment. Any device that insulates the reaction from the outside environment can serve as a calorimeter. The most basic type consists of a Styrofoam coffee cup, while more sophisticated calorimeters are used for more accurate work. 

Thermal probes can be constructed quite easily and cheaply. Their response is non-directional, and very small devices with diameters between 0.5 and 1 mm can be fashioned. They are very simple to use with almost every kind of ultrasonic equipment and measurements can be made very rapidly. Several kinds of thermal probes have been described which are basically thermocouples or thermistors used bare or embedded in an absorbing medium. Bare probes are used to measure the actual temperature of the medium, just as in a calorimeter. Coated probes will generate internal heat under the influence of the sound wave and are used to determine local power dissipation in the absence of stirring. Coated probes are often used in conjunction with a bare probe, and the temperature difference between the two probes is then proportional to the acoustic power. Great care should be taken since the response of a coated probe strongly depends on its nature and geometry, and on the medium used. 

Calorimeters are devices that are commonly used to measure the heating value of fuels. For example, a Junkers flow calorimeter is used to measure the heating value of gaseous fuels. A bomb calorimeter, on the other hand, is used to measure the heating value of liquid or solid fuels, such as kerosene, heatii oil, or coal. Perform a search to obtain information about these two types of calorimeters. Write a brief report discussing the principles behind the operation of these calorimeters. 

A simpler device than the constant-volume calorimeter is the constant-pressure calorimeter, which is used to determine the heat changes for noncombustion reactions. A crude constant-pressure calorimeter can be constructed from two Styrofoam coffee cups, as shown in Figure 6.9. This device measures the heat effects of a variety of reactions, such as acid-base neutralization, as well as the heat of solution and heat of dilution. Because the pressure is constant, the heat change for the process is equal to the enthalpy change MI). As in the case of a constant-volume calorimeter, we treat the calorimeter as an isolated system. Furthermore, we neglect the small heat capacity of the coffee cups in our calculations. Table 6.3 lists some reactions that have been studied with the constant-pressure calorimeter. 

Constant-Volume Calorimetry Constant-volume calorimetry is often carried out in a bomb calorimeter, a device conunonly used to measure the heat of combustion reactions, such as for fuels and foods. In the coffee-cup calorimeter, we assume all the heat is absorbed by the water, but in reality, some must be absorbed by the stirrer, thermometer, and so forth. With the much more precise bomb calorimeter, the heat capacity of the entire calorimeter is known (or can be determined). 

To measure the heat flow in a reaction, a device known as a calorimeter is used. The apparatus contains water and/or other materials of known heat capacity. The walls of the calorimeter are insulated so that there is no exchange of heat with the surrounding air. It follows that the only heat flow is between the reaction system and the calorimeter. The heat flow for the reaction system is equal in magnitude but opposite in sign to that of the calorimeter ... 

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