Heat - and the flow of heat is zero if T S = T E . Figure...

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Heat Two bodies brought in thermal contact will change their temperature until they are at the same temperature. In the process of reaching thermal equilibrium , heat is transferred from one body to the other. Suppose we have a system of interest at temperature T S surrounded by an environment with temperature T E . If T S > T E heat flows from the system to the environment. If T S < T E heat flows from the environment into the system. Heat, presented by the symbol Q and unit Joule, is chosen to be positive when heat flows into the system, and negative if heat flows out of the system (see Figure 17.1). Heat flow is a results of a temperature difference between two bodies,
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Unformatted text preview: and the flow of heat is zero if T S = T E . Figure 17.1. Heat Flow. Heat is not the only way in which energy can be transferred between a system and its environment. Energy can also be transferred between a system and its environment by means of work (W). The unit of work is the Joule. Another commonly used unit is the calorie. The calorie is defined as the amount of heat that would raise the temperature of 1 g of water from 14.5 C to 15.5 C. The Joule and the calorie are related as follows: 1 cal = 4.1860 J...
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This document was uploaded on 11/25/2011.

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