Question

For a particular process q = 20 kJ and w = 15 kJ. Which of the following statements is true? A. Heat flows from the system to the surroundings. B. The system does work on the surroundings. C. ΔE = 35 kJ D. All of the above are true. E. None of the above are true.

a) A only
b) B only
c) C only
d) D only

Answer 1

The question pertains to the first law of thermodynamics and the correct statements are that heat flows into the system and the system does work on the surroundings. However, the calculated change in internal energy is 5 kJ, not 35 kJ, so none of the statements provided in the question are true.

Step-by-step explanation:

The student is asking about the first law of thermodynamics concerning the energy changes that occur within a system in a process. In thermodynamics, the change in internal energy (ΔE) of a system is given by the formula ΔE = q - w, where 'q' represents the heat exchanged and 'w' represents the work done. In this situation, if q = 20 kJ (heat added to the system) and w = 15 kJ (work done by the system), applying the formula gives ΔE = q - w = 20 kJ - 15 kJ = 5 kJ.

Therefore, the correct statements would be:

• A. Heat flows into the system from the surroundings, because q is positive.
• B. The system does work on the surroundings, because w is positive.

However, statement C is not true because ΔE is not equal to 35 kJ but 5 kJ. So the correct answer is:

E. None of the above are true.

Which corresponds to the option 'e) None of the above are true' from the question's list of choices.