Understanding Energy Transfer: System vs Surroundings

Question:

Which of the following is true if δesys = 445 J?

a) The system is gaining 445 J, while the surroundings are losing 445 J.

b) Both the system and the surroundings are losing 445 J.

c) Both the system and the surroundings are gaining 445 J.

d) The system is losing 445 J, while the surroundings are gaining 445 J.

e) None of the above is true.

Answer:

If δesys = 445 J, the system is gaining 445 J, while the surroundings are losing 445 J, as per the conservation of energy.

Explanation:

If δesys = 445 J, this means there is a change in the internal energy of the system by 445 joules. According to the first law of thermodynamics, energy cannot be created or destroyed, only transferred or transformed. Therefore, if the system gains 445 J, the surroundings must lose an equivalent amount of energy to conserve the total energy, and vice versa.

In this scenario, the correct statement is: a) The system is gaining 445 J, while the surroundings are losing 445 J. This implies that the energy is being transferred to the system from the surroundings, increasing the system's internal energy by 445 joules, while the surroundings' energy decreases by the same amount.