Question

Piston in Water Bath Conceptual Work-Energy Problem Imagine a piston containing a sample of ideal gas in thermal equilibrium with a large water bath. Assume that the piston head is perfectly free to move unless locked in place, and the walls of the piston readily allow the transfer of energy via heat unless wrapped in insulation. The piston head is unlocked and the gas is in an equilibrium state.

For each of the actions described below, state whether the work W done on the gas, the heat energy Qtransferred to the gas, and the change in the internal energy ?Eth of the gas are positive (+), negative (?), or zero (0). After each action the piston is reset to its initial equilibrium state. Throughout this item we will assume that the first law of thermodynamics is given by ?Eth=W+Q?. Part A Action: Lock the piston head in place. Hold the piston above a very hot flame. Enter the signs of W, Q, and ?Eth Use +, ?, or 0 separated by commas. For example, if Wis positive, Q is negative, and ?Eth is zero, you would type +,-,0. Part B Action: Very slowly push the piston head down. Keep the piston is in constant thermal equilibrium with a large water bath. Enter the signs of W, Q, and ?Eth Use +, ?, or 0 separated by commas. For example, if Wis positive, Q is negative, and ?Eth is zero, you would type +,-,0. Part C Action: Lock the piston head in place. Plunge the piston into very cold water. Enter the signs of W, Q, and ?Eth Use +, ?, or 0 separated by commas. For example, if Wis positive, Q is negative, and ?Eth is zero, you would type +,-,0. Part D Action: Wrap the piston in insulation. Pull the piston head up. Enter the signs of W, Q, and ?Eth Use +, ?, or 0 separated by commas. For example, if Wis positive, Q is negative, and ?Eth is zero, you would type +,-,0.

Answer 1