Exam 18: The First Law of Thermodynamics

The temperature of an ideal gas in a sealed 0.40-m³ rigid container is reduced from 350 K to 270k The final pressure of the gas is 60 kPA. The molar heat capacity at constant volume of the gas is 28.0 J/mol · K. The heat absorbed by the gas is closest to

The temperature of an ideal gas in a sealed 0.40 m³ container is reduced from 400 K to 270 K. The final pressure of the gas is 30 kPA. The molar heat capacity at constant volume of the gas is 28.0 J/mol · K. The work done by the gas is closest to

During an isothermal process, 5.0 J of heat is removed from an ideal gas. How much work does the gas do during this process?

The process shown in the pV diagram in the figure is an

A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from 0.020 m³ to 0.040 m³. The final pressure is 120 kPA. The ideal gas constant is R = 8.314 J/mol ∙ K. The heat transfer to the gas is closest to

A steel container, equipped with a piston, contains 21 mol of an ideal gas at 465 K. The container is compressed isothermally to 90% of its original volume. How much work is done on the gas? The ideal gas constant is R = 8.314 J/mol ∙ K.

When a fixed amount of ideal gas goes through an isochoric process

In an isochoric process, the internal (thermal) energy of an ideal gas decreases by 50 J. How much heat is exchanged with the gas during this process?

A compression, at a constant pressure of 190 kPa, is performed on 5.0 moles of an ideal monatomic gas. The compression reduces the volume of the gas from 0.19 m³ to 0.12 m³. The ideal gas constant is R = 8.314 J/mol ∙ K. The work done by the gas is closest to

An ideal gas in a balloon is kept in thermal equilibrium with its constant-temperature surroundings. How much work is done by the gas if the outside pressure is slowly reduced, allowing the balloon to expand to 6.0 times its original size? The balloon initially has a pressure of 645.0 Pa and a volume of 0.10 m³. The ideal gas constant is R = 8.314 J/mol ∙ K.

The process shown in the pV diagram in the figure is

The figure shows a pV diagram for 0.95 mol of gas that undergoes the process 1 → 2. The gas then undergoes an isochoric heating from point 2 until the pressure is restored to the value it had at point 1. What is the final temperature of the gas? The ideal gas constant is R = 8.314 J/mol ∙ K = 0.0821 L ∙ atm/mol ∙ K.

During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas?

The pV diagram shown is for 7.50 moles of an ideal diatomic gas taken through a cycle from a to b to c. The ideal gas constant is R = 8.314 J/mol ∙ K. (a) What is the highest temperature reached by the gas during the cycle? (b) What net work does the gas do during the cycle? (c) How much heat is exchanged with the gas during part bc of the cycle? Does it enter or leave the gas? (d) What is the change in the internal (thermal) energy of the gas during part bc of the cycle? (e) What is the change in the internal (thermal) energy of the gas during the entire cycle?

The process shown in the T-V diagram in the figure is an

When a fixed amount of ideal gas goes through an isobaric expansion

A cylinder contains 1.2 moles of ideal gas, initially at a temperature of 116°C. The cylinder is provided with a frictionless piston, which maintains a constant pressure of 6.4 × 10⁵ Pa on the gas. The gas is cooled until its temperature has decreased to 27°C. For the gas C_V = 11.65 J/mol ∙ K, and the ideal gas constant R = 8.314 J/mol ∙ K. (a) Find the work done by (or on) the gas during this process. Is the work done by or on the gas? (b) What is the change in the internal (thermal) energy of the gas during this process? (c) How much heat is transferred to (or from) the gas during this process? Does this heat flow into or out of the gas?

An ideal gas with γ = 1.30 occupies 7.0 L at 300 K and 200 kPa pressure. It is compressed adiabatically to 1/7 of its original volume, then cooled at constant volume to 300 K, and finally allowed to expand isothermally to 7.0 L. How much work does the gas do during this process? The ideal gas constant is R = 8.314 J/mol ∙ K = 0.0821 L ∙ atm/mol ∙ K.

A container of ideal gas has a movable frictionless piston. This container is placed in a very large water bath and slowly compressed so that the temperature of the gas remains constant and equal to the temperature of the water. Which of the following statements about this gas are true for this process? (There may be more than one correct choice.)

An ideal monatomic gas cools from 455.0 K to 405.0 K at constant volume as 831 J of energy is removed from it. How many moles of gas are in the sample? The ideal gas constant is R = 8.314 J/mol ∙ K.