Styrofoam, environment

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. 

Benzene found in the environment is from both human activities and natural processes. Benzene was first discovered and isolated from coal tar in the 1800s. Today, benzene is made mostly from petroleum sources. Because of its wide use, benzene ranks in the top 20 in production volume for chemicals produced in the United States. Various industries use benzene to make other chemicals, such as styrene (for Styrofoam and other plastics), cumene (for various resins), and cyclohexane (for nylon and synthetic fibers). Benzene is also used for the manufacturing of some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene, which include volcanoes and forest fires, also contribute to the presence of benzene in the environment. Benzene is also a part of crude oil and gasoline and cigarette smoke. For more information on the nature and uses of benzene, see Chapters 3 and 4. 

Adding cenospheres and Styrofoam up to 10wt%, its thermal conductivity can be lowered to half that of conventional cement. When Ceramicrete-based permafrost sealant was cured in a CO2 environment, it set well, and when stored in CO2 for a week, it did not show any deterioration. Sugama and CarcieUo [8] predict that these sealants are durable up to 20 years in a downhole environment, compared to conventional cements that last for only a year. Unlike conventional cements, because CBS are neutral in pH and are not affected by downhole hydrocarbon gases, they are ideal for use in the gas hydrate regions in arctic climates. 

A piece of iron weighing 72.4 g is heated to 100.0°C and plunged into 100.0 g water that is initially at 10.0°C in a Styrofoam cup calorimeter. Assume no heat is lost to the Styrofoam cup or to the environment (Fig. 12.8). Calculate the final temperature that is... 

The heat leak into the test line from the natural environment could be limited through the use of Styrofoam insulation. In six out of the ten tests reported, data were obtained with uninsulated lines which resulted in higher heat leaks than for the tests in which insulation was used. 

For many aqueous reactions, we can measure AH xn fairly simply using a coffee-cup calorimeter shown in Figure 6.9 . The calorimeter consists of two Styrofoam coffee cups, one inserted into the other, to provide insulation from the laboratory environment. The calorimeter is equipped with a thermometer and a stirrer. The reaction occurs in a specifically measured quantity of solution within the calorimeter, so that the mass of the solution is known. During the reaction, the heat evolved (or absorbed) causes a temperature change in the solution, which the thermometer measures. If we know the specific heat capacity of the solution, normally assumed to be that of water, we can calculate the heat absorbed by or lost from the solution (which is acting as the surroundings) using the equation ... 

In the tests conducted above room temperature (30 and 50 °C), the environmental chamber was placed on a table in the ambient environment. The Chromalox controller sitting on top of the chamber turned two 25-W light bulbs on and off as needed to maintain the desired temperature (Fig. 6). Only in the tests conducted at 50 °C were all sides of the environmental chambers insulated with Styrofoam boards to reduce heating loss. 

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