Which of the following is a statement of the first law of thermodynamics?

[A] Ek = ½ mV2

[B] A negative ΔH corresponds to an exothermic process. [C] ΔE = Efinal - Einitial

[D] Energy lost by the system must be gained by the surroundings.

[E] 1 cal = 4.184 J (exactly)

Option D.

Explanation:

The first law of thermodynamics is a law of conservation of energy. This automatically tells us that energy lost by a system won't dissapear, but it will be gained by the surroundings.

Mathematically is stated this way:

ΔU=Q-W

Where ΔU is the change in the internal energy of a closed system, Q is the amount of heat supplied and W the amount of work done by the system on its surroundings. It means that if the internal energy U decreases, then that energy lost must have been converted to work W in the surroundings.