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Unformatted text preview: your answer be if the piston were not free to move?
7–171 Reconsider Prob. 7–170. Using EES (or other)
software, compare the results for constant specific heats to those obtained using built-in variable specific
heats built into EES functions.
7–172 Repeat Prob. 7–170 by assuming the piston is made of
5 kg of copper initially at the average temperature of the two
gases on both sides.
7–173 An insulated 5-m3 rigid tank contains air at 500 kPa
and 57°C. A valve connected to the tank is now opened, and air
is allowed to escape until the pressure inside drops to 200 kPa.
The air temperature during this process is maintained constant
by an electric resistance heater placed in the tank. Determine
(a) the electrical energy supplied during this process and
(b) the total entropy change.
Answers: (a) 1501 kJ, (b) 4.40 kJ/K neck of the bottle is now opened and the atmospheric air is
allowed to flow into the bottle. The air trapped in the bottle
eventually reaches thermal equilibrium with the atmosphere as
a result of heat transfer through the wall of the bottl...
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This document was uploaded on 11/28/2012.
- Spring '09