Chapter 4: Problem 45
Is the energy required to heat air from 295 to \(305 \mathrm{K}\) the same as the energy required to heat it from 345 to \(355 \mathrm{K} ?\) Assume the pressure remains constant in both cases.
Chapter 4: Problem 45
Is the energy required to heat air from 295 to \(305 \mathrm{K}\) the same as the energy required to heat it from 345 to \(355 \mathrm{K} ?\) Assume the pressure remains constant in both cases.
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Get started for freeThe average specific heat of the human body is \(3.6 \mathrm{kJ} / \mathrm{kg} \cdot^{\circ} \mathrm{C} .\) If the body temperature of an \(80-\mathrm{kg}\) man rises from \(37^{\circ} \mathrm{C}\) to \(39^{\circ} \mathrm{C}\) during strenuous exercise, determine the increase in the thermal energy of the body as a result of this rise in body temperature.
A 6 -pack canned drink is to be cooled from \(18^{\circ} \mathrm{C}\) to \(3^{\circ} \mathrm{C} .\) The mass of each canned drink is 0.355 kg. The drinks can be treated as water, and the energy stored in the aluminum can itself is negligible. The amount of heat transfer from the 6 canned drinks is \((a) 22 \mathrm{kJ}\) (b) \(32 \mathrm{kJ}\) \((c) 134 \mathrm{kJ}\) \((d) 187 \mathrm{kJ}\) \((e) 223 \mathrm{kJ}\)
Consider a well-insulated horizontal rigid cylinder that is divided into two compartments by a piston that is free to move but does not allow either gas to leak into the other side. Initially, one side of the piston contains \(1 \mathrm{m}^{3}\) of \(\mathrm{N}_{2}\) gas at \(500 \mathrm{kPa}\) and \(120^{\circ} \mathrm{C}\) while the other side contains \(1 \mathrm{m}^{3}\) of He gas at \(500 \mathrm{kPa}\) and \(40^{\circ} \mathrm{C}\). Now thermal equilibrium is established in the cylinder as a result of heat transfer through the piston. Using constant specific heats at room temperature, determine the final equilibrium temperature in the cylinder. What would your answer be if the piston were not free to move?
A gas is compressed from an initial volume of \(0.42 \mathrm{m}^{3}\) to a final volume of \(0.12 \mathrm{m}^{3} .\) During the quasi-equilibrium process, the pressure changes with volume according to the relation \(P=a V+b,\) where \(a=-1200 \mathrm{kPa} / \mathrm{m}^{3}\) and \(b=600 \mathrm{kPa}\) Calculate the work done during this process ( \(a\) ) by plotting the process on a \(P\) - \(V\) diagram and finding the area under the process curve and ( \(b\) ) by performing the necessary integrations.
A piston-cylinder device initially contains \(0.35-\mathrm{kg}\) steam at \(3.5 \mathrm{MPa}\), superheated by \(7.4^{\circ} \mathrm{C}\). Now the steam loses heat to the surroundings and the piston moves down, hitting a set of stops at which point the cylinder contains saturated liquid water. The cooling continues until the cylinder contains water at \(200^{\circ} \mathrm{C}\). Determine \((a)\) the final pressure and the quality (if mixture), \((b)\) the boundary work, \((c)\) the amount of heat transfer when the piston first hits the stops, \((d)\) and the total heat transfer.
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