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 Q transferred to the gas, and the change in the internal energy ΔEth 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 ΔEth=W+Q

Required:
Lock the piston head in place. Hold the piston above a very hot flame. Write down the signs of W, Q, and ΔEth Use +, -, or 0 separated by commas. For example, if Wis positive, Q is negative, and ΔEth is zero, you would type +,-,0.