Question

Which statement defines the first law of thermodynamics?

a
The total energy of the universe is constant.
b
The entropy (or randomness) of the universe is always increasing.
c
The absolute entropy (or randomness) of a perfect crystal of a pure substance is 0 at 0 K.
d
In a chemical reaction that proceeds completely to the products, the total mass of the reactants is equal to the total mass of the products.

Answer 1

The answer should be A. "The first law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are subject to the principle of the conservation of energy." (LiveScience) Basically, energy cannot be created nor destroyed, only changed in its form.