22. The First Law of Thermodynamics

Cyclic Thermodynamic Processes

22. The First Law of Thermodynamics

Cyclic Thermodynamic Processes

Guided videos.

Learn with Patrick

Go to the course

Guided course

Properties of Cyclic Thermodynamic Processes

08:45

Properties of Cyclic Thermodynamic Processes

Signs in a Three-Step Cyclic Process

Heat Added Over Complete Cycle

Practice this topic

Multiple Choice

An ideal gas is taken through the four processes shown below. The changes in internal energy for three of these processes are as follows: ΔE_AB = +82 J; ΔE_BC = +15 J; ΔE_DA = –56 J. Find the change in internal energy for the process from C to D.

0.25 mol of a gas are compressed at a constant pressure of 250 kPa from 6000 cm^3 to 2000 cm^3, then expanded at a constant temperature back to 6000 cm^3. What is the net work done on the gas?

144

views

Textbook Question

A heat engine using a diatomic gas follows the cycle shown in FIGURE P21.55. Its temperature at point 1 is 20℃. a. Determine Wₛ, Q, and ∆Eₜₕ for each of the three processes in this cycle. Display your results in a table.

176

views

Textbook Question

(II) An ideal gas expands at a constant total pressure of 2.5 atm from 410 mL to 690 mL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed to drop until the temperature reaches its original value. Calculate

(a) the total work done by the gas in the process, and

(b) the total heat flow into the gas.

views

Textbook Question

(II) A 1.0-L volume of air initially at 3.5 atm of (gauge)pressure is allowed to expand isothermally until the (gauge) pressure is 1.0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to its original pressure by heating at constant volume.

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

views

Textbook Question

FIGURE P19.62 shows a thermodynamic process followed by 120 mg of helium. c. How much heat energy is transferred to or from the gas during each of the three segments?

views

Textbook Question

Work Done in a Cyclic Process. (a) In Fig. 19.7a, consider the closed loop 1 → 3 → 2 → 4 → 1. This is a cyclic process in which the initial and final states are the same. Find the total work done by the system in this cyclic process, and show that it is equal to the area enclosed by the loop.

1003

views

Textbook Question

. BIO Work Done by the Lungs. The graph in Fig. E19.4 shows a pV-diagram of the air in a human lung when a person is inhaling and then exhaling a deep breath. Such graphs, obtained in clinical practice, are normally somewhat curved, but we have modeled one as a set of straight lines of the same general shape. (Important: The pressure shown is the gauge pressure, not the absolute pressure.) (b) The process illustrated here is somewhat different from those we have been studying, because the pressure change is due to changes in the amount of gas in the lung, not to temperature changes. (Think of your own breathing. Your lungs do not expand because they've gotten hot.) If the temperature of the air in the lung remains a reasonable 20°C, what is the maximum number of moles in this person's lung during a breath?

412