A monatomic ideal gas undergoes an isothermal expansion at 300 K,as the volume increased from to The final pressure of the gas is The ideal gas constant is .The change in the internal (thermal)energy of the gas is closest to
A) 0.00 kJ.
B) 12 kJ.
C) 25 kJ.
D) -12 kJ.
E) -25 kJ.

Question

A monatomic ideal gas undergoes an isothermal expansion at 300 K,as the volume increased from  to  The final pressure of the gas is  The ideal gas constant is  .The change in the internal (thermal)energy of the gas is closest to
A) 0.00 kJ. 
B) 12 kJ. 
C) 25 kJ. 
D) -12 kJ. 
E) -25 kJ.

Quizplus · Accepted Answer

Since the process is isothermal, the temperature of the gas remains constant. Therefore, the internal energy change is zero. The first law of thermodynamics states that the change in internal energy of a system equals the heat added to the system minus the work done by the system. In this case, the gas is expanding against a constant external pressure, so work is being done by the system. However, since the temperature is constant, the heat added to the system must be equal to the work done by the system, and the internal energy change is zero. Therefore, the correct answer is A) 0.00 kJ.

A Monatomic Ideal Gas Undergoes an Isothermal Expansion at 300