Cyclic Thermodynamic Processes Practice Problems

A 0.32 mol gas sample experiences isobaric compression at 2.20 atm from V = 5.00 L to V = 1.50L, followed by isothermal expansion to the starting volume of 5.00 liters. Calculate the sum of work done on the gas.

A thermal engine utilizes 1.5 mol of neon gas as its operating fluid. The pV diagram shown below illustrates the cyclic process of the engine. Calculate the temperatures at points A, B, and C.

A thermal engine uses helium as the working fluid. At point A, helium is initially at a temperature of 300 K while the temperature at point C is 750 K. The pV diagram of the thermal engine's cyclic transformation is shown below. Calculate the heat Q during the transformation AB. Hint: Calculate W and ΔE_int first.

The pV diagram of a cyclic transformation of 1.0 mole of helium gas is shown below. The work produced during the cycle is 80 J. Determine V_min.

A sample of helium gas expands under constant pressure conditions of about 4.0 atm from an initial volume of 500 mL, reaching a final volume of 950 mL. The gas then cools down at constant volume until it returns to its original temperature state again. Calculate how much work was performed by this sample during these processes and find out how much heat was transferred.

A 2.0-L sample of nitrogen gas is initially at a pressure of 5.0 atm (gauge pressure). The gas undergoes a three-step process as follows:

i. The gas is allowed to expand isothermally until the pressure drops to 1.5 atm (gauge pressure).

ii. The gas is then compressed at constant pressure back to its initial volume.

iii. Finally, the gas is heated at constant volume until it reaches its original pressure.

Draw the process on a 𝑃𝑉 diagram, including numbers and labels for the axes.

0.20 grams of neon is treated through the thermodynamics paths shown below. Calculate the net heat energy that flows into/out of the gas in the three-step process.

A closed-loop or cyclic process is a process that starts and ends at the same point. The system returns to its initial state implying that initial and final states are the same.  The PV diagram below shows the cyclic process for a gas sample. Determine the net work done by the gas during the process and verify that its magnitude is equal to the area of the loop. 

A model of the lungs can be made using a balloon inside a container fitted with a movable piston. The balloon is connected to the atmosphere using a pipe. Air is sucked into the balloon when the piston is lowered and expelled when the piston is raised. An idealized curve with straight lines instead of curves for sucking and expulsion is shown below. Note: The curve is labeled using gauge pressure rather than absolute pressure. Determine the net work done by the ballon in one cycle. 

A model of the lungs is made of a balloon, a glass container, and a movable diaphragm. A straw is used to connect the balloon to the atmosphere. The balloons are inflated when the diaphragm is pulled downward and deflated when the diaphragm is released. An ideal PV diagram for the process is shown below. The actual PV diagram has curves, not straight lines. The pressure used is gauge pressure, not absolute pressure. This process differs from other processes in that pressure variations are caused by changes in the quantity of gas rather than changes in temperature. If the model is operated at a temperature of 25°C, determine the greatest number of moles of gas attained in the balloon.